Comedi Documentation: Application-specific functions

Should be understandable: open the device, get the data, print it out. This is basically the guts of demo/inp.c, without error checking or fancy options. -Compile it using

By now, the comedi_read_data() line looks a little archaic, using -the UNIX file descriptor cf->fd instead of just cf. (By the -way, somewhere in the heart of comedi_open() is the line -cf->fd=open(filename,O_RDWR).) Well, there isn't one good -replacement, since it highly depends on your application -what additional features you might want in a comedi_get() -replacement. But this is the topic of a different section.

Many data acquisition devices have the capability to directly control acquisition using either an on-board timer or an external triggering input. Comedi commands are used to control this kind -of acquisition. The same structure (comedi_cmd) used to control -acquisition is used to query the capabilities of a device.

Commands specify a particular data acquisition sequence, which is comprised of a number of scans. Each scan is comprised of a number of conversions, which usually corresponds to a single @@ -118,41 +124,120 @@ A/D or D/A conversion. The start and end of the sequence, and the start and end of each scan, and each conversion is called an event.

Each of these 5 types of events are caused by a triggering -source. The source types are:

For every trigger, there is a corresponding +argument (the *_arg members of the +comedi_cmd +structure) whose meaning depends on the type of trigger. The meanings +of the arguments are as follows:

Not all triggers are applicable to all events. Supported triggers for specific events depends significantly on your particular -device. In addition, for every trigger type, there is a cooresponding -argument that specifies the rate, the count, which external signal, -etc.

TRIG_FOLLOW is a special type of trigger for scan_begin events that -triggers on the next lower level trigger, in this case, the trigger -for convert events. It may or may not be supported. Later, it may -also be used for start events if you want to chain multiple commands.

In particular, scan_end events will almost always be triggered on -TRIG_COUNT, with the argument being the number of channels in the -scan. (Actually, samples in the scan, since on most boards you can -measure a single channel multiple times in a scan.) Also, until -otherwise supported, start events can only be TRIG_NOW.

TRIG_NONE is typically used only as a stop_src. The arg for TRIG_NONE +is reserved and should be set to 0.

TRIG_NOW is most often used as a start_src. The arg for TRIG_NOW is +the number of nanoseconds between when the command is issued and when +the event should occur. In the case of using TRIG now as a start_src, +it indicates a delay between issuing the command and the start of +acquisition. Most drivers only support a delay of 0.

TRIG_FOLLOW is a special type of trigger for events that trigger on +the completion of some other, logically connected event. The argument +is reserved and should be set to 0. When used +as a scan_begin_src, it indicates that a trigger should occur as a +logical continuation of convert events. This is done in order to +properly describe boards that do not have separate timers for +convert and scan_begin events. When used as a start_src for analog +output subdevices, it indicates that conversion of output samples +should begin when samples are written to the buffer.

TRIG_TIMER is most often used as a convert_src, a scan_begin_src, or +both. It indicates that triggers should occur at a specific rate. +The argument specifies the interval between triggers in nanoseconds.

TRIG_COUNT is used for scan_end_src and stop_src. It indicates that +a trigger should occur when the specified number of corresponding +lower-level triggers (convert and scan_begin, respectively) occur. +The argument is the count of lower-level triggers.

TRIG_EXT can be useful as any of the trigger sources. It indicates +that an external digital line should be used to trigger the event. +The exact meaning of digital line is device-dependent. Some devices +have one dedicated line, others may allow generic digital input +lines to be used. The argument indicates the particular external +line to use as the trigger.

TRIG_INT is typically used as a start_src. This trigger occurs when +the application performs an INSN_INTTRIG instruction. Using TRIG_INT +is a method by which the application can accurately record the time of +the start of acquisition, since the parsing and setup time of a +particular command may be significant. The argument associated with +TRIG_INT is reserved and should be set to 0.

TRIG_OTHER can be useful as any of the trigger sources. The exact +meaning of TRIG_OTHER is driver-specific, and implements a feature +that otherwise does not fit into the command interface. Configuration +of TRIG_OTHER features are done by INSN_CONFIG insns. The argument +is reserved and should be set to 0.

The chanlist member of the +comedi_cmd +structure should point to an array whose number of elements is specificed by chanlist_len +(this will generally be the same as the scan_end_arg). +The chanlist specifies the sequence of channels and gains (and analog references) +that should be stepped through for each scan. The elements of the chanlist array +should be initialized by packing the channel, range and reference information +together with the +CR_PACK(channel, range, aref) macro.

The final member of the +comedi_cmd structure is 'flags'. +The following flags are valid, and can be bitwise-or'd together.

6. Comedilib reference

6. Libcomedi Reference

6.1 Constants and Macros +

CR_PACK(channel, range, aref)

RANGE_LENGTH() (deprecated)

Rangetype values are library-internal tokens that represent an +array of range information structures. These numbers are primarily +used for communication between the kernel and library.

The RANGE_LENGTH() macro returns the length of the array that is +specified by the rangetype token.

The RANGE_LENGTH() macro is deprecated, and should not be used in +new applications. It is scheduled to be removed from the header +file at version 1.0. Binary compatibility may be broken for version +1.1.

6.2 Data Types and Structures +

comedi_t

The data type comedi_t is used to represent an open Comedi +device. A valid comedi_t pointer is returned by a successful +call to comedi_open(), and should be used for subsequent +access to the device. +It is a transparent type, and pointers to type comedi_t +should not be dereferenced by the application.

sampl_t

The data type sampl_t is one of the generic types used to represent +data values in libcomedi. It is used in a few places where a shorter +data type is useful, but is limited to 16 bits on the i386 architecture.

lsampl_t

The data type lsampl_t is one of the generic types used to represent +data values in libcomedi. It is currently defined to be unsigned int.

comedi_trig_struct (deprecated)

The comedi_trig structure is a control structure used by the +COMEDI_TRIG ioctl, an older method of communicating +instructions to the driver and hardware. Use of comedi_trig is +deprecated, and should not be used in new applications.

comedi_sv_t

6.1 comedi_loglevel() -

The comedi_sv_t structure is used by the comedi_sv_*() +functions to provide a simple method of accurately measuring +slowly varying inputs. See the relevant section for more +details.

This function affects the output of debugging and error messages -from comedlib. By increasing the loglevel, additional debugging -information will be printed. This function returns the previous -loglevel. Some debugging information will only be printed if -comedilib was compiled with this debugging information included. -The loglevel can also be affected by the environment -variable COMEDI_LOGLEVEL. The meaning of the loglevels is as -follows: -

Comedilib prints an error message whenever an invalid -parameter is passed to comedilib. -

Comedilib prints an error message whenever an error is generated -in the comedilib library or is generated in the C library when -called by comedilib. -

6.2 comedi_open -

Opens a comedi device specified by the filename fn. Returns NULL -on error. Returns a handle that is given as a parameter to other -comedilib functions. -

void comedi_perror(const char *s); -char *comedi_strerror(int errnum); -int comedi_errno(void); -

When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -comedi_errno(). This error number can be -converted to a human-readable form by the functions -comedi_perror() and comedi_strerror(). -

These functions are intended to mimic the behavior of the -standard C library functions perror(), -strerror, and errno(). In particular, -comedilib functions sometimes return an error that is generated -inside the C library; the comedi error message in this case -is the same as the C library. -

The function comedi_perror() prints an error -message to stderr. The error message consists of the -argument string, a colon, a space, a description of the error -condition, and a new line. -

The function comedi_strerror() returns a pointer to a -character string -describing the comedilib error errnum. The persistence -of the returned pointer is undefined, and should not be trusted -after the next comedilib call. An unrecognized error number will -return a pointer to the string "undefined error", or similar. -

The function comedi_errno() -returns an integer describing the most recent comedilib error. This -integer may be used as the errnum parameter for -comedi_strerror(). -

6.3 comedi_fileno() -

The function comedi_fileno -returns the integer descriptor for the handle it. If -it is an invalid comedi_t pointer, the function -returns -1 and sets the appropriate comedilib error value. -

6.4 comedi_get_n_subdevices() -

comedi_cmd

The function comedi_get_n_subdevices returns the -number of subdevices associated with the comedi descriptor -it, or -1 if there is an error. -

6.5 comedi_get_version_code() -

The function comedi_get_version_code() returns the -version code of the currently running comedi module. The version -code is of the form 0x010203, which is the version code for -version 1.2.3. -

6.6 comedi_get_driver_name() -

The function comedi_get_driver_name returns a pointer -to a string containing the name of the driver being used by comedi -for the comedi device represented by it. This pointer is -valid until the comedi descriptor it is closed. This -function returns NULL if there is an error. -

6.7 comedi_get_board_name() -

The function comedi_get_board_name returns a pointer -to a string containing the name of the device. This pointer is -valid until the comedi descriptor it is closed. This -function returns NULL if there is an error. -

6.8 comedi_get_subdevice_type() -

The function comedi_get_subdevice_type() returns an -integer describing the type of subdevice that belongs to the comedi -device it and has the index subdevice. The -function returns -1 is there is an error. -

6.9 comedi_find_subdevice_by_type() -

int comedi_find_subdevice_by_type(comedi_t *it,int type,unsigned int start_subdevice) -

The function comedi_find_subdevice_by_type tries to -locate a subdevice belonging to comedi device it, -having type type, starting with the subdevice -start_subdevice. If it finds the requested subdevice, -it returns its index. If it does not locate the requested -subdevice, it returns -1 and sets the comedi error number to -"subdevice not found". If there is an error, the function -returns -1 and sets the appropriate error. -

For subdevice types, see the manual page for the function -comedi_get_subdevice_type(). -

6.10 comedi_get_n_channels() -

comedi_insn

The function comedi_get_n_channels() returns the number -of channels of the subdevice belonging to the comedi device it -and having index subdevice. This function returns -1 on error. -

6.11 comedi_get_maxdata() -

lsampl_t comedi_get_maxdata(comedi_t *it,unsigned int subdevice,unsigned int chan); -

The function comedi_get_maxdata() returns the maximum -valid data value for channel chan of subdevice -subdevice belonging to the comedi device it -This function returns 0 on error. -

6.12 comedi_get_rangetype() -

int comedi_get_rangetype(comedi_t *it,unsigned int subdevice,unsigned int chan); -

The function comedi_get_rangetype() returns an integer -that represents the number of range specifications available for a -particular channel, as well as a conversion table to convert sample -values to/from physical units. The macro -RANGE_LENGTH(rangetype) -can be used to determine the number of range specifications for a given -range type. -

6.13 comedi_get_range() -

comedi_range * comedi_get_range(comedi_t *it,unsigned int subdevice,unsigned int chan,unsigned int range); -

The function comedi_get_range returns a pointer to a -comedi_range structure that contains information that can be used to -convert sample values to or from physical units. The pointer is valid -until the comedi device it is closed. If there is an -error, NULL is returned. -

6.14 comedi_trigger() -

The function comedi_trigger() instructs comedi to -perform the command specified by the trigger structure -trig. Results depend on the particular command -being issued. If there is an error, -1 is returned. -

Complete information about comedi commands is given in the -manual page comedi(8). -

double comedi_to_phys(lsampl_t data,comedi_range *rng,lsampl_t maxdata); -lsampl_t comedi_from_phys(double data,comedi_range *rng,lsampl_t maxdata); -

The functions comedi_to_phys() and -comedi_from_phys() convert sample values to/from physical -units. The parameter rng represents the conversion -information to use, and the parameter maxdata represents -the maximum possible data value for the channel that the data was read/ -will be written to. -

6.15 comedi_data_read() + + +

comedi_range

6.3 Functions

int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan, -unsigned int range,unsigned int aref,lsampl_t *data); -int comedi_data_write(comedi_t *it,unsigned int subd,unsigned int chan, -unsigned int range,unsigned int aref,lsampl_t data); -

comedi_close()

The return type of this function will change to int, in +order to match fclose.

comedi_command()

comedi_command_test()

comedi_data_read()

int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan,
+unsigned int range,unsigned int aref,lsampl_t *data);

Reads a single sample on the channel that is specified by the comedi device it, the subdevice subd, and the channel chan. -For the operation, +For the A/D conversion (if appropriate), the device is configured to use range specification range and (if appropriate) analog reference type aref. Analog reference types that are not supported -by the device are silently ignored. -

The function comedi_data_read() reads one data value from -the specified channel and places the +by the device are silently ignored.

comedi_data_read() reads one data value from +the specified channel and places the data value that is read in the location pointed to by -data. -

On sucess, comedi_data_read() returns 0. If there is an +error, -1 is returned.

Valid data values returned by these function is an unsigned integer +less than or equal to maxdata, which is channel-dependent. +Conversion of these data value to physical units can be performed +by


+comedi_to_phys()

comedi_data_write()

int comedi_data_write(comedi_t *it,unsigned int subd,unsigned int chan,
+unsigned int range,unsigned int aref,lsampl_t data);

Writes a single sample on the channel that +is specified by the comedi device it, the +subdevice subd, and the channel chan. +For the D/A conversion (if appropriate), the device is +configured to use range specification +range and (if appropriate) analog reference type +aref. Analog reference types that are not supported +by the device are silently ignored.

comedi_data_write() writes the data value specified by the argument data to -the specified channel. -

On sucess, comedi_data_write() returns 0. If there is an error, -1 is +returned.

Valid data values used by these functions is an unsigned integer less than or equal to maxdata, which is channel-dependent. -Conversion of these data values to physical units can be performed -by comedi_to_phys() and comedi_from_phys(). -

6.16 comedi_sv_init() -

The special functions comedi_sv_*() are designed to -make it easy to accurately measure slowly varying analog inputs. -A slowly -varying input is one that is effectively constant over the course -of approximately 100 A/D conversions. However, since these -conversions can sometimes be pre-empted by scheduling, for most -purposes, a slowly varying signal should be effectively constant -for greater than 20 ms (the default Linux timeslice). -

By averaging many A/D conversions of a relatively constant -signal, it is possible to get a better measurement of the signal -than a single A/D conversion. In general, the uncertainty of the -measurement decreases as the square root of the number of samples. -This is limited by the rate that which the signal varies, and -ultimately by the spurious free dynamic range of the A/D converter. -

6.17 comedi_get_timer() -

comedi_dio_bitfield();

int comedi_dio_bitfield(comedi_t *it,unsigned int subd,unsigned
+int write_mask,unsigned int *bits);

The function comedi_dio_bitfield() allows multiple channels to +be read simultaneously from a digital input or digital I/O device. +The parameter write_mask and the value pointed to by bits +are interpreted as bit fields, with the least significant bit +representing channel 0. For each bit in write_mask that is +set, the cooresponding bit in *bits is written to the digital +output channel. Each digital input channel is read, and the result +placed in the approprate bits in *bits.

The current implementation reads and writes bits using separate +system calls, which is not ideal. When the kernel driver supports +simultaneous reading/writing, this will be fixed in the library.

It should be noted that it is not possible to access channels +greater than 31 using this function.

comedi_dio_config()

int comedi_dio_config(comedi_t *it,unsigned int subd,unsigned
+int chan,unsigned int dir);

The function comedi_dio_config configures individual channels +in a digital I/O subdevice to be either input or output, depending +on the value of parameter dir. Depending on the capabilities +of the hardware device, multiple channels may be affected by +a single call to comedi_dio_config.

comedi_dio_read()

int comedi_dio_read(comedi_t *it,unsigned int subd,unsigned int
+chan,unsigned int *bit);

The function reads the status of channel chan belonging to the digital +input subdevice subd of device it. The result, 0 or 1, is stored +in bit. Returns -1 on failure.

comedi_dio_write()

int comedi_dio_write(comedi_t *it,unsigned int subd,unsigned
+int chan,unsigned int bit);

The function writes the value of bit, 0 or 1, to channel chan, +belonging to the digital output device subd of device it. Returns +-1 on failure.

comedi_fileno()

The function comedi_fileno +returns the integer descriptor for the handle it. It +is equivalent to the standard function fileno. If +it is an invalid comedi_t pointer, the function +returns -1 and sets the appropriate libcomedi error value.

comedi_find_range()

int comedi_find_range(comedi_t *it, unsigned int subdevice, unsigned
+int chan, unsigned int unit, double min, double max);

The function comedi_find_range tries to +locate the optimal (smallest) range for the channel chan +belonging to a subdevice of the comedi device it, +that includes both min and max in units. +If it finds a matching range, it returns its index. If no +matching range is available, it returns -1.

comedi_errno()

The function comedi_errno() +returns an integer describing the most recent comedilib error. This +integer may be used as the errnum parameter for +


+comedi_strerror()

When a libcomedi function fails, it usually returns -1 or +NULL, depending on the return type. An internal library +variable stores an error number, which can be retrieved with +comedi_errno(). This error number can be +converted to a human-readable form by the functions +


+comedi_perror()

+and


+comedi_strerror()

These functions are intended to mimic the behavior of the +standard C library functions perror(), +strerror, and errno(). In particular, +libcomedi functions sometimes return an error that is generated +by the C library; the Comedi error message in this case +is the same as the C library.

comedi_find_subdevice_by_type()

int comedi_find_subdevice_by_type(comedi_t *it,int type,unsigned int
+start_subdevice);

The function comedi_find_subdevice_by_type tries to +locate a subdevice belonging to comedi device it, +having type type, starting with the subdevice +start_subdevice. If it finds the requested subdevice, +it returns its index. If it does not locate the requested +subdevice, it returns -1 and sets the comedi error number to +"subdevice not found". If there is an error, the function +returns -1 and sets the appropriate error.

comedi_from_phys()

Converts data given in physical units (data) into sample values +(lsampl_t, between 0 and maxdata). The parameter rng +represents the conversion information to use, and the parameter +maxdata represents the maximum possible data value for the +channel that the data will be written to.

comedi_get_board_name()

The function comedi_get_board_name returns a pointer +to a string containing the name of the device. This pointer is +valid until the comedi descriptor it is closed. This +function returns NULL if there is an error.

comedi_get_cmd_src_mask()

int comedi_get_cmd_src_mask(comedi_t *dev, unsigned int subdevice,
+comedi_cmd *cmd);

comedi_get_driver_name()

The function comedi_get_driver_name returns a pointer +to a string containing the name of the driver being used by comedi +for the comedi device represented by it. This pointer is +valid until the comedi descriptor it is closed. This +function returns NULL if there is an error.

comedi_get_maxdata()

lsampl_t comedi_get_maxdata(comedi_t *it,unsigned int
+subdevice,unsigned int chan);

The function comedi_get_maxdata() returns the maximum +valid data value for channel chan of subdevice +subdevice belonging to the comedi device it +This function returns 0 on error.

comedi_get_n_channels()

The function comedi_get_n_channels() returns the number +of channels of the subdevice belonging to the comedi device it +and having index subdevice. This function returns -1 on error.

comedi_get_n_ranges()

int comedi_get_n_ranges(comedi_t *it,unsigned int subdevice, unsigned int
+chan);

The function comedi_get_n_ranges() returns the number +of ranges of the channel chan belonging to the subdevice +of the comedi device it. This function returns -1 on error.

comedi_get_n_subdevices()

The function comedi_get_n_subdevices returns the +number of subdevices associated with the comedi descriptor +it, or -1 if there is an error.

comedi_get_range()

comedi_range * comedi_get_range(comedi_t *it,unsigned int subdevice,unsigned int chan,unsigned int
+range);

The function comedi_get_range returns a pointer to a +comedi_range structure that contains information that can be used to +convert sample values to or from physical units. The pointer is valid +until the comedi device it is closed. If there is an +error, NULL is returned.

comedi_get_rangetype() deprecated

int comedi_get_rangetype(comedi_t *it,unsigned int subdevice,unsigned int
+chan);

The function comedi_get_rangetype() returns an integer +that represents the number of range specifications available for a +particular channel chan of the subdevice subdevice, as well as a conversion table to convert sample +values to/from physical units.

The macro +RANGE_LENGTH(rangetype) +can be used to determine the number of range specifications for a given +range type.

comedi_get_subdevice_type()

The function comedi_get_subdevice_type() returns an +integer describing the type of subdevice that belongs to the comedi +device it and has the index subdevice. The +function returns -1 is there is an error.

comedi_get_timer() (deprecated)

int comedi_get_timer(comedi_t *it,unsigned int subdev, double
+freq,unsigned int *trigvar, double *actual_freq);

The function comedi_get_timer converts the frequency freq +to a number suitable to send to the driver in a comedi_trig +structure. This function remains for compatibility with very +old versions of Comedi, that converted sampling rates to timer +values in the libary. This conversion is now done in the kernel, +and every device has the timer type nanosec_timer, indicating +that timer values are simply a time specified in nanoseconds.

comedi_get_version_code()

The function comedi_get_version_code() returns the +version code of the currently running comedi module. The version +code is of the form 0x01072b, which is the version code for +version 1.7.43.

This function is of limited usefulness. A typical mis-application +of this function is to use it to determine if a certain feature is +supported. If the application needs +to know of the existence of a particular feature, an existence +test function should be written and put in the libcomedi source.

comedi_loglevel()

This function affects the output of debugging and error messages +from libcomedi. By increasing the loglevel, additional debugging +information will be printed. This function returns the previous +loglevel. Error messages and debugging are printed to the +stream stderr. The loglevel can also be affected by the +environment variable COMEDI_LOGLEVEL.

In order to conserve resources, some debugging information is +disabled when libcomedi is compiled.

comedi_open()

Opens a comedi device specified by the filename filename. +Returns NULL on error. On sucess, it returns a handle that is +given as a parameter to other libcomedi functions.

You are not supposed to have access to the internals of the +comedi_t structure.

comedi_perror()

When a comedilib function fails, it usually returns -1 or +NULL, depending on the return type. An internal library +variable stores an error number, which can be retrieved with +


+comedi_errno()

. +This error number can be +converted to a human-readable form by the functions +comedi_perror() +and


+comedi_strerror()

These functions are intended to mimic the behavior of the +standard C library functions perror(), +strerror, and errno(). In particular, +comedilib functions sometimes return an error that is generated +inside the C library; the comedi error message in this case +is the same as the C library.

The function comedi_perror() prints an error +message to stderr. The error message consists of the +argument string, a colon, a space, a description of the error +condition, and a new line.

comedi_strerror()

When a comedilib function fails, it usually returns -1 or +NULL, depending on the return type. An internal library +variable stores an error number, which can be retrieved with +


+comedi_errno()

. This error number can be +converted to a human-readable form by the functions +


+comedi_perror()

+and comedi_strerror().

The function comedi_strerror() returns a pointer to a +character string +describing the comedilib error errnum. The persistence +of the returned pointer is undefined, and should not be trusted +after the next libcomedi call. An unrecognized error number will +return a pointer to the string "undefined error", or similar.

comedi_sv_init()

int comedi_sv_init(comedi_sv_t *sv,comedi_t *dev,unsigned int subd,
+unsigned int chan);

comedi_sv_init initializes the slow varying comedi structure +sv of the device dev, the subdevice subd (analog input) and +the channel chan. +The slow varying comedi structure sv of type


+comedi_sv_t

+specifies the signal measurement. The default number of averaged +samples is 100. Returns zero on success, -1 on error.

comedi_sv_update()

The function comedi_sv_update updates the slow varying comedi structure +sv. +Returns zero on success, -1 on error.

int comedi_sv_measure()

comedi_sv_measure measures the slow variing signal. The measurement +is specified by the slow varying comedi structure sv, the result is +stored in data. +On success returns the number of samples, -1 on error.

comedi_to_phys()

Converts data given in sample values (lsampl_t, between 0 and +maxdata) into physical units (double). The parameter rng +represents the conversion information to use, and the parameter +maxdata represents the maximum possible data value for the +channel that the data was read.

comedi_trigger() (deprecated)

The function comedi_trigger instructs comedi to +perform the command specified by the +trigger structure trig. Results depend on +the particular command being issued. If there is an +error, -1 is returned.

comedi_get_subdevice_flags()

This function returns a bitfield describing the capabilities of the +specified subdevice. If there is an error, -1 is returned.

comedi_range_is_chan_specific()

If each channel of the specified subdevice has a different range +specification, this function returns 1. Otherwise, this function +returns 0. On error, this function returns -1.

Undocumented functions

Comedi Documentation

David Schleef, ds@stm.lbl.gov

David Schleef ds@stm.lbl.gov, +Frank Hess fmhess@uiuc.edu

1. Introduction

5. Application-specific functions

6. Libcomedi Reference

1. Libcomedi Reference

1.1 Constants and Macros -

RANGE_LENGTH() (deprecated)

Rangetype values are library-internal tokens that represent an -array of range information structures. These numbers are primarily -used for communication between the kernel and library.

The RANGE_LENGTH() macro returns the length of the array that is -specified by the rangetype token.

The RANGE_LENGTH() macro is deprecated, and should not be used in -new applications. It is scheduled to be removed from the header -file at version 1.0. Binary compatibility may be broken for version -1.1.

1.2 Data Types and Structures -

comedi_t

The data type comedi_t is used to represent an open Comedi -device. A valid comedi_t pointer is returned by a successful -call to comedi_open(), and should be used for subsequent -access to the device. -It is a transparent type, and pointers to type comedi_t -should not be dereferenced by the application.

sampl_t

The data type sampl_t is one of the generic types used to represent -data values in libcomedi. It is used in a few places where a shorter -data type is useful, but is limited to 16 bits on the i386 architecture.

lsampl_t

The data type lsampl_t is one of the generic types used to represent -data values in libcomedi. It is currently defined to be unsigned int.

comedi_trig_struct (deprecated)

The comedi_trig structure is a control structure used by the -COMEDI_TRIG ioctl, an older method of communicating -instructions to the driver and hardware. Use of comedi_trig is -deprecated, and should not be used in new applications.

comedi_sv_t

The comedi_sv_t structure is used by the comedi_sv_*() -functions to provide a simple method of accurately measuring -slowly varying inputs. See the relevant section for more -details.

comedi_cmd

comedi_insn

comedi_range

1.3 Functions -

comedi_close()

The return type of this function will change to int, in -order to match fclose.

comedi_data_read()

int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan,
-unsigned int range,unsigned int aref,lsampl_t *data);

Reads a single sample on the channel that -is specified by the comedi device it, the -subdevice subd, and the channel chan. -For the A/D conversion (if appropriate), -the device is configured to use range specification -range and (if appropriate) analog reference type -aref. Analog reference types that are not supported -by the device are silently ignored.

comedi_data_read() reads one data value from -the specified channel and places the -data value that is read in the location pointed to by -data.

On sucess, comedi_data_read() returns 0. If there is an -error, -1 is returned.

Valid data values returned by these function is an unsigned integer -less than or equal to maxdata, which is channel-dependent. -Conversion of these data value to physical units can be performed -by


-comedi_to_phys()

comedi_data_write()

int comedi_data_write(comedi_t *it,unsigned int subd,unsigned int chan,
-unsigned int range,unsigned int aref,lsampl_t data);

Writes a single sample on the channel that -is specified by the comedi device it, the -subdevice subd, and the channel chan. -For the D/A conversion (if appropriate), the device is -configured to use range specification -range and (if appropriate) analog reference type -aref. Analog reference types that are not supported -by the device are silently ignored.

comedi_data_write() writes the data value -specified by the argument data to -the specified channel.

On sucess, comedi_data_write() returns 0. If there is an error, -1 is -returned.

Valid data values used by these functions is an unsigned integer -less than or equal to maxdata, which is channel-dependent. -Conversion of physical units to these data value can be performed -by


-comedi_from_phys()

comedi_dio_bitfield();

int comedi_dio_bitfield(comedi_t *it,unsigned int subd,unsigned
-int write_mask,unsigned int *bits);

The function comedi_dio_bitfield() allows multiple channels to -be read simultaneously from a digital input or digital I/O device. -The parameter write_mask and the value pointed to by bits -are interpreted as bit fields, with the least significant bit -representing channel 0. For each bit in write_mask that is -set, the cooresponding bit in *bits is written to the digital -output channel. Each digital input channel is read, and the result -placed in the approprate bits in *bits.

The current implementation reads and writes bits using separate -system calls, which is not ideal. When the kernel driver supports -simultaneous reading/writing, this will be fixed in the library.

It should be noted that it is not possible to access channels -greater than 31 using this function.

comedi_dio_config()

int comedi_dio_config(comedi_t *it,unsigned int subd,unsigned
-int chan,unsigned int dir);

The function comedi_dio_config configures individual channels -in a digital I/O subdevice to be either input or output, depending -on the value of parameter dir. Depending on the capabilities -of the hardware device, multiple channels may be affected by -a single call to comedi_dio_config.

comedi_dio_read()

int comedi_dio_read(comedi_t *it,unsigned int subd,unsigned int
-chan,unsigned int *bit);

The function reads the status of channel chan belonging to the digital -input subdevice subd of device it. The result, 0 or 1, is stored -in bit. Returns -1 on failure.

comedi_dio_write()

int comedi_dio_write(comedi_t *it,unsigned int subd,unsigned
-int chan,unsigned int bit);

The function writes the value of bit, 0 or 1, to channel chan, -belonging to the digital output device subd of device it. Returns --1 on failure.

comedi_fileno()

The function comedi_fileno -returns the integer descriptor for the handle it. It -is equivalent to the standard function fileno. If -it is an invalid comedi_t pointer, the function -returns -1 and sets the appropriate libcomedi error value.

comedi_find_range()

int comedi_find_range(comedi_t *it, unsigned int subdevice, unsigned
-int chan, unsigned int unit, double min, double max);

The function comedi_find_range tries to -locate the optimal (smallest) range for the channel chan -belonging to a subdevice of the comedi device it, -that includes both min and max in units. -If it finds a matching range, it returns its index. If no -matching range is available, it returns -1.

comedi_errno()

The function comedi_errno() -returns an integer describing the most recent comedilib error. This -integer may be used as the errnum parameter for -


-comedi_strerror()

When a libcomedi function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -comedi_errno(). This error number can be -converted to a human-readable form by the functions -


-comedi_perror()

-and


-comedi_strerror()

These functions are intended to mimic the behavior of the -standard C library functions perror(), -strerror, and errno(). In particular, -libcomedi functions sometimes return an error that is generated -by the C library; the Comedi error message in this case -is the same as the C library.

comedi_find_subdevice_by_type()

int comedi_find_subdevice_by_type(comedi_t *it,int type,unsigned int
-start_subdevice);

comedi_from_phys()

Converts data given in physical units (data) into sample values -(lsampl_t, between 0 and maxdata). The parameter rng -represents the conversion information to use, and the parameter -maxdata represents the maximum possible data value for the -channel that the data will be written to.

comedi_get_board_name()

comedi_get_driver_name()

comedi_get_maxdata()

lsampl_t comedi_get_maxdata(comedi_t *it,unsigned int
-subdevice,unsigned int chan);

The function comedi_get_maxdata() returns the maximum -valid data value for channel chan of subdevice -subdevice belonging to the comedi device it -This function returns 0 on error.

comedi_get_n_channels()

The function comedi_get_n_channels() returns the number -of channels of the subdevice belonging to the comedi device it -and having index subdevice. This function returns -1 on error.

comedi_get_n_ranges()

int comedi_get_n_ranges(comedi_t *it,unsigned int subdevice, unsigned int
-chan);

The function comedi_get_n_ranges() returns the number -of ranges of the channel chan belonging to the subdevice -of the comedi device it. This function returns -1 on error.

comedi_get_n_subdevices()

The function comedi_get_n_subdevices returns the -number of subdevices associated with the comedi descriptor -it, or -1 if there is an error.

comedi_get_range()

comedi_range * comedi_get_range(comedi_t *it,unsigned int subdevice,unsigned int chan,unsigned int
-range);

comedi_get_rangetype() deprecated

int comedi_get_rangetype(comedi_t *it,unsigned int subdevice,unsigned int
-chan);

The function comedi_get_rangetype() returns an integer -that represents the number of range specifications available for a -particular channel chan of the subdevice subdevice, as well as a conversion table to convert sample -values to/from physical units.

The macro -RANGE_LENGTH(rangetype) -can be used to determine the number of range specifications for a given -range type.

comedi_get_subdevice_type()

comedi_get_timer() (deprecated)

int comedi_get_timer(comedi_t *it,unsigned int subdev, double
-freq,unsigned int *trigvar, double *actual_freq);

The function comedi_get_timer converts the frequency freq -to a number suitable to send to the driver in a comedi_trig -structure. This function remains for compatibility with very -old versions of Comedi, that converted sampling rates to timer -values in the libary. This conversion is now done in the kernel, -and every device has the timer type nanosec_timer, indicating -that timer values are simply a time specified in nanoseconds.

comedi_get_version_code()

The function comedi_get_version_code() returns the -version code of the currently running comedi module. The version -code is of the form 0x01072b, which is the version code for -version 1.7.43.

This function is of limited usefulness. A typical mis-application -of this function is to use it to determine if a certain feature is -supported. If the application needs -to know of the existence of a particular feature, an existence -test function should be written and put in the libcomedi source.

comedi_loglevel()

This function affects the output of debugging and error messages -from libcomedi. By increasing the loglevel, additional debugging -information will be printed. This function returns the previous -loglevel. Error messages and debugging are printed to the -stream stderr. The loglevel can also be affected by the -environment variable COMEDI_LOGLEVEL.

In order to conserve resources, some debugging information is -disabled when libcomedi is compiled.

comedi_open()

Opens a comedi device specified by the filename filename. -Returns NULL on error. On sucess, it returns a handle that is -given as a parameter to other libcomedi functions.

You are not supposed to have access to the internals of the -comedi_t structure.

comedi_perror()

When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -


-comedi_errno()

. -This error number can be -converted to a human-readable form by the functions -comedi_perror() -and


-comedi_strerror()

The function comedi_perror() prints an error -message to stderr. The error message consists of the -argument string, a colon, a space, a description of the error -condition, and a new line.

comedi_strerror()

When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -


-comedi_errno()

. This error number can be -converted to a human-readable form by the functions -


-comedi_perror()

-and comedi_strerror().

The function comedi_strerror() returns a pointer to a -character string -describing the comedilib error errnum. The persistence -of the returned pointer is undefined, and should not be trusted -after the next libcomedi call. An unrecognized error number will -return a pointer to the string "undefined error", or similar.

comedi_sv_init()

int comedi_sv_init(comedi_sv_t *sv,comedi_t *dev,unsigned int subd,
-unsigned int chan);

comedi_sv_init initializes the slow varying comedi structure -sv of the device dev, the subdevice subd (analog input) and -the channel chan. -The slow varying comedi structure sv of type


-comedi_sv_t

-specifies the signal measurement. The default number of averaged -samples is 100. Returns zero on success, -1 on error.

comedi_sv_update()

The function comedi_sv_update updates the slow varying comedi structure -sv. -Returns zero on success, -1 on error.

int comedi_sv_measure()

comedi_sv_measure measures the slow variing signal. The measurement -is specified by the slow varying comedi structure sv, the result is -stored in data. -On success returns the number of samples, -1 on error.

comedi_to_phys()

Converts data given in sample values (lsampl_t, between 0 and -maxdata) into physical units (double). The parameter rng -represents the conversion information to use, and the parameter -maxdata represents the maximum possible data value for the -channel that the data was read.

comedi_trigger() (deprecated)

The function comedi_trigger instructs comedi to -perform the command specified by the -trigger structure trig. Results depend on -the particular command being issued. If there is an -error, -1 is returned.

comedi_get_subdevice_flags()

This function returns a bitfield describing the capabilities of the -specified subdevice. If there is an error, -1 is returned.

comedi_range_is_chan_specific()

If each channel of the specified subdevice has a different range -specification, this function returns 1. Otherwise, this function -returns 0. On error, this function returns -1.

Undocumented functions

2. Reference Comedilib-0.7.9: types

2.1 sampl_t -

2.2 comedi_sv_t -

3. Reference Comedilib-0.7.9: structures

3.1 comedi_trig_struct -

3.2 comedi_sv_struct -

4. Reference Comedilib-0.7.9: functions

4.1 comedi_close() -

4.2 comedi_data_read() -

int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan,
-unsigned int range,unsigned int aref,lsampl_t *data);

Reads a single sample on the channel that -is specified by the comedi device it, the -subdevice subd, and the channel chan. -For the operation, -the device is configured to use range specification -range and (if appropriate) analog reference type -aref. Analog reference types that are not supported -by the device are silently ignored. -

comedi_data_read() reads one data value from -the specified channel and places the -data value that is read in the location pointed to by -data. -

On sucess, comedi_data_read() returns 0. If there is an error, -1 is -returned. -

Valid data values used by these function is an unsigned integer -less than or equal to maxdata, which is channel-dependent. -Conversion of these data value to physical units can be performed -by


-comedi_to_phys()

. -

4.3 comedi_data_write() -

int comedi_data_write(comedi_t *it,unsigned int subd,unsigned int chan,
-unsigned int range,unsigned int aref,lsampl_t data);

Writes a single sample on the channel that -is specified by the comedi device it, the -subdevice subd, and the channel chan. -For the operation, -the device is configured to use range specification -range and (if appropriate) analog reference type -aref. Analog reference types that are not supported -by the device are silently ignored. -

comedi_data_write() writes the data value -specified by the argument data to -the specified channel. -

On sucess, comedi_data_write() returns 0. If there is an error, -1 is -returned. -

Valid data values used by these functions is an unsigned integer -less than or equal to maxdata, which is channel-dependent. -Conversion of physical units to these data value can be performed -by


-comedi_from_phys()

. -

4.4 comedi_dio_bitfield(); -

int comedi_dio_bitfield(comedi_t *it,unsigned int subd,unsigned int write_mask, -unsigned int *bits); -

4.5 comedi_dio_config() -

int comedi_dio_config(comedi_t *it,unsigned int subd,unsigned int chan,unsigned int dir); -

The function comedi_dio_config configures the direction dir of -channel chan belonging to the configurable digital input/output subdevice -subd of the device it. Returns -1 on failure. -

4.6 comedi_dio_read() -

int comedi_dio_read(comedi_t *it,unsigned int subd,unsigned int chan,unsigned int *bit); -

The function reads the status of channel chan belonging to the digital -input subdevice subd of device it. The result, 0 or 1, is stored -in bit. Returns -1 on failure. -

4.7 comedi_dio_write() -

int comedi_dio_write(comedi_t *it,unsigned int subd,unsigned int chan,unsigned int bit); -

The function writes the value of bit, 0 or 1, in channel chan, -belonging to the digital output device subd of device it. Returns --1 on failure. -

4.8 comedi_fileno() -

The function comedi_fileno -returns the integer descriptor for the handle it. If -it is an invalid comedi_t pointer, the function -returns -1 and sets the appropriate comedilib error value. -

4.9 comedi_find_range() -

int comedi_find_range(comedi_t *it, unsigned int subdevice, unsigned
-int chan, unsigned int unit, double min, double max);

The function comedi_find_range tries to -locate the optimal (smallest) range of a channel chan belonging to a -subdevice of the comedi device it, which includes the data -range between min and max in units with highest -precision. If it finds a matching range, -it returns its index. If no matching range is available, it returns -1. -

4.10 comedi_errno() -


-comedi_perror()

-and


-comedi_strerror()

. -

The function comedi_errno() -returns an integer describing the most recent comedilib error. This -integer may be used as the errnum parameter for -


-comedi_strerror()

. -

4.11 comedi_find_subdevice_by_type() -

int comedi_find_subdevice_by_type(comedi_t *it,int type,unsigned int
-start_subdevice);

4.12 comedi_from_phys() -

lsampl_t comedi_from_phys(double data, comedi_range *rng, lsampl_t maxdata); -

Converts data given in physical units (double) into sample values (lsampl_t, between 0 and maxdata). -The parameter rng represents the conversion information to use, and the parameter maxdata represents -the maximum possible data value for the channel that the data will be written to. -

4.13 comedi_get_board_name() -

4.14 comedi_get_driver_name() -

4.15 comedi_get_maxdata() -

lsampl_t comedi_get_maxdata(comedi_t *it,unsigned int subdevice,unsigned int
-chan);

The function comedi_get_maxdata() returns the maximum -valid data value for channel chan of subdevice -subdevice belonging to the comedi device it -This function returns 0 on error. -

4.16 comedi_get_n_channels() -

The function comedi_get_n_channels() returns the number -of channels of the subdevice belonging to the comedi device it -and having index subdevice. This function returns -1 on error. -

4.17 comedi_get_n_ranges() -

int comedi_get_n_ranges(comedi_t *it,unsigned int subdevice, unsigned int
-chan);

The function comedi_get_n_ranges() returns the number -of ranges of the channel chan belonging to the subdevice -of the comedi device it. This function returns -1 on error. -

4.18 comedi_get_n_subdevices() -

The function comedi_get_n_subdevices returns the -number of subdevices associated with the comedi descriptor -it, or -1 if there is an error. -

4.19 comedi_get_range() -

comedi_range * comedi_get_range(comedi_t *it,unsigned int subdevice,unsigned int chan,unsigned int
-range);

4.20 comedi_get_rangetype() -

int comedi_get_rangetype(comedi_t *it,unsigned int subdevice,unsigned int
-chan);

The macro -RANGE_LENGTH(rangetype) -can be used to determine the number of range specifications for a given -range type. -

4.21 comedi_get_subdevice_type() -

4.22 comedi_get_timer() -

comedi_get_timer returns the type of the timer of the subdevice -subdev of the device it , -

4.23 comedi_get_version_code() -

The function comedi_get_version_code() returns the -version code of the currently running comedi module. The version -code is of the form 0x01072b, which is the version code for -version 1.7.43. -

4.24 comedi_loglevel() -

Comedilib prints an error message whenever an invalid -parameter is passed to comedilib. -

Comedilib prints an error message whenever an error is generated -in the comedilib library or is generated in the C library when -called by comedilib. -

4.25 comedi_open() -

Opens a comedi device specified by the filename fn. Returns NULL -on error. Returns a handle that is given as a parameter to other -comedilib functions. -

4.26 comedi_perror() -

When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -


-comedi_errno()

. -This error number can be -converted to a human-readable form by the functions -comedi_perror() -and


-comedi_strerror()

. -

The function comedi_perror() prints an error -message to stderr. The error message consists of the -argument string, a colon, a space, a description of the error -condition, and a new line. -

4.27 comedi_strerror() -

When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -


-comedi_errno()

. This error number can be -converted to a human-readable form by the functions -


-comedi_perror()

-and comedi_strerror(). -

4.28 comedi_sv_init() -

int comedi_sv_init(comedi_sv_t *sv,comedi_t *dev,unsigned int subd,
-unsigned int chan);

The special functions comedi_sv_*() are designed to -make it easy to accurately measure slowly varying analog inputs. -A slowly varying input is one that is effectively constant over the course -of approximately 100 A/D conversions. However, since these -conversions can sometimes be pre-empted by scheduling, for most -purposes, a slowly varying signal should be effectively constant -for greater than 20 ms (the default Linux timeslice). -

comedi_sv_init initializes the slow varying comedi structure -sv of the device dev, the subdevice subd (analog input) and -the channel chan. -The slow varying comedi structure sv of type


-comedi_sv_t

-specifies the signal measurement. Default number of averaged samples is 100. -Returns zero on success, -1 on error. -

4.29 comedi_sv_update() -

comedi_sv_update updates the slow varying comedi structure -sv. -Returns zero on success, -1 on error. -

4.30 int comedi_sv_measure() -

4.31 comedi_to_phys() -

Converts data given in sample values (lsampl_t, between 0 and maxdata) into physical units (double). -The parameter rng represents the conversion information to use, and the parameter maxdata represents -the maximum possible data value for the channel that the data was read. -

4.32 comedi_trigger() -

The function comedi_trigger() instructs comedi to -perform the command specified by the -trigger structure -trig. Results depend on the particular command -being issued. If there is an error, -1 is returned. -

Complete information about comedi commands is given in the -manual page comedi(8). -

4.33 comedi_get_timer() -

Comedi Documentation

David Schleef, ds@stm.lbl.gov

1. Libcomedi Reference

-Comedi Documentation -<author>David Schleef, <tt/ds@stm.lbl.gov/ - - - - -<sect>Libcomedi Reference - - -<sect1>Constants and Macros - - - -<sect2>RANGE_LENGTH() <it/(deprecated)/ - -<label id="RANGE_LENGTH"> - -<tt/RANGE_LENGTH(rangetype)/ - - -Rangetype values are library-internal tokens that represent an -array of range information structures. These numbers are primarily -used for communication between the kernel and library. - - -The RANGE_LENGTH() macro returns the length of the array that is -specified by the rangetype token. - - -The RANGE_LENGTH() macro is deprecated, and should not be used in -new applications. It is scheduled to be removed from the header -file at version 1.0. Binary compatibility may be broken for version -1.1. - - - -<sect1>Data Types and Structures - - -<sect2>comedi_t -<label id="comedi_t"> - - -The data type <tt/comedi_t/ is used to represent an open Comedi -device. A valid <tt/comedi_t/ pointer is returned by a successful -call to <tt/comedi_open()/, and should be used for subsequent -access to the device. -It is a transparent type, and pointers to type <tt/comedi_t/ -should not be dereferenced by the application. - - - -<sect2>sampl_t -<label id="sampl_t"> - - -The data type <tt/sampl_t/ is one of the generic types used to represent -data values in libcomedi. It is used in a few places where a shorter -data type is useful, but is limited to 16 bits on the i386 architecture. - - - -<sect2>lsampl_t -<label id="lsampl_t"> - - -The data type <tt/lsampl_t/ is one of the generic types used to represent -data values in libcomedi. It is currently defined to be <tt/unsigned int/. - - - - - -<sect2>comedi_trig_struct <it/(deprecated)/ -<label id="comedi_trig_struct"> - - -The <tt/comedi_trig/ structure - -<tscreen><verb> -struct comedi_trig_struct{ - unsigned int subdev; /* subdevice */ - unsigned int mode; /* mode */ - unsigned int flags; - unsigned int n_chan; /* number of channels */ - unsigned int *chanlist; /* channel/range list */ - sampl_t *data; /* data list, size depends on subd flags */ - unsigned int n; /* number of scans */ - unsigned int trigsrc; - unsigned int trigvar; - unsigned int trigvar1; - unsigned int data_len; - unsigned int unused[3]; -} -</verb></tscreen> - -The <tt/comedi_trig/ structure is a control structure used by the -COMEDI_TRIG ioctl, an older method of communicating -instructions to the driver and hardware. Use of comedi_trig is -deprecated, and should not be used in new applications. - - -This structure is defined as part of the Comedi kernel interface. - - -<sect2>comedi_sv_t -<label id="comedi_sv_t"> - - -<tscreen><verb> -struct comedi_sv_struct{ - comedi_t *dev; - unsigned int subdevice; - unsigned int chan; - - /* range policy */ - int range; - int aref; - - /* number of measurements to average (for ai) */ - int n; - - lsampl_t maxdata; -} -</verb></tscreen> - -The <tt/comedi_sv_t/ structure is used by the <tt/comedi_sv_*()/ -functions to provide a simple method of accurately measuring -slowly varying inputs. See the relevant section for more -details. - - - -<sect2>comedi_cmd -<label id="comedi_cmd"> - - -undocumented - - -Related functions are described in section XXX. - - -This structure is defined as part of the Comedi kernel interface. - - -<sect2>comedi_insn -<label id="comedi_insn"> - - -undocumented - - -Related functions are described in section XXX. - - -This structure is defined as part of the Comedi kernel interface. - - - -<sect2>comedi_range -<label id="comedi_range"> - - -undocumented - - - -<sect1>Functions - - -<sect2>comedi_close() -<label id="comedi_close"> - - -<tt>void comedi_close(comedi_t *it);</tt> - - -Closes a device previously opened by comedi_open(). - - -The return type of this function will change to <tt/int/, in -order to match <tt/fclose/. - - -Source: <tt>/lib/comedi.c</tt> - - -<sect2>comedi_data_read() -<label id="comedi_data_read"> - - -<tt>int comedi_data_read(comedi_t *it,unsigned int subd,unsigned int chan, - unsigned int range,unsigned int aref,lsampl_t *data);</tt> - - -Reads a single sample on the channel that -is specified by the comedi device <tt>it</tt>, the -subdevice <tt>subd</tt>, and the channel <tt>chan</tt>. -For the A/D conversion (if appropriate), -the device is configured to use range specification -<tt>range</tt> and (if appropriate) analog reference type -<tt>aref</tt>. Analog reference types that are not supported -by the device are silently ignored. - - -<tt>comedi_data_read()</tt> reads one data value from -the specified channel and places the -data value that is read in the location pointed to by -<tt>data</tt>. - - -On sucess, <tt>comedi_data_read()</tt> returns 0. If there is an -error, -1 is returned. - - -Valid analog reference numbers are: - -<itemize> -<item>AREF_GROUND Reference to analog ground -<item>AREF_COMMON Reference to analog common -<item>AREF_DIFF Differential reference -<item>AREF_OTHER Board-specific meaning -</itemize> - -Valid data values returned by these function is an unsigned integer -less than or equal to <tt>maxdata</tt>, which is channel-dependent. -Conversion of these data value to physical units can be performed -by <tt><ref id="comedi_to_phys" name = -"comedi_to_phys()"></tt>. - -Source: <tt>/lib/data.c</tt> - - -<sect2>comedi_data_write() - - -<tt>int comedi_data_write(comedi_t *it,unsigned int subd,unsigned int chan, - unsigned int range,unsigned int aref,lsampl_t data);</tt> - - -Writes a single sample on the channel that -is specified by the comedi device <tt/it/, the -subdevice <tt/subd/, and the channel <tt/chan/. -For the D/A conversion (if appropriate), the device is -configured to use range specification -<tt/range/ and (if appropriate) analog reference type -<tt/aref/. Analog reference types that are not supported -by the device are silently ignored. - -<tt/comedi_data_write()/ writes the data value -specified by the argument <tt/data/ to -the specified channel. - -On sucess, <tt>comedi_data_write()</tt> returns 0. If there is an error, -1 is -returned. - -Valid analog reference numbers are: - -<itemize> -<item>AREF_GROUND Reference to analog ground -<item>AREF_COMMON Reference to analog common -<item>AREF_DIFF Differential reference -<item>AREF_OTHER Board-specific meaning -</itemize> - -Valid data values used by these functions is an unsigned integer -less than or equal to <tt>maxdata</tt>, which is channel-dependent. -Conversion of physical units to these data value can be performed -by <tt><ref id="comedi_from_phys" name = -"comedi_from_phys()"></tt>. - -Source: <tt>/lib/data.c</tt> - - - -<sect2>comedi_dio_bitfield(); - - -<tt/int comedi_dio_bitfield(comedi_t *it,unsigned int subd,unsigned -int write_mask,unsigned int *bits);/ - - -The function <tt/comedi_dio_bitfield()/ allows multiple channels to -be read simultaneously from a digital input or digital I/O device. -The parameter <tt/write_mask/ and the value pointed to by <tt/bits/ -are interpreted as bit fields, with the least significant bit -representing channel 0. For each bit in <tt/write_mask/ that is -set, the cooresponding bit in <tt/*bits/ is written to the digital -output channel. Each digital input channel is read, and the result -placed in the approprate bits in <tt/*bits/. - - -The current implementation reads and writes bits using separate -system calls, which is not ideal. When the kernel driver supports -simultaneous reading/writing, this will be fixed in the library. - - -It should be noted that it is not possible to access channels -greater than 31 using this function. - - -Source: <tt>/lib/dio.c</tt> - - - -<sect2>comedi_dio_config() - -<tt/int comedi_dio_config(comedi_t *it,unsigned int subd,unsigned -int chan,unsigned int dir);/ - - -The function <tt/comedi_dio_config/ configures individual channels -in a digital I/O subdevice to be either input or output, depending -on the value of parameter <tt/dir/. Depending on the capabilities -of the hardware device, multiple channels may be affected by -a single call to <tt/comedi_dio_config/. - - -Valid directions are: -<itemize> -<item> COMEDI_INPUT -<item> COMEDI_OUTPUT -</itemize> - -Source: <tt>/lib/dio.c</tt> - - - -<sect2>comedi_dio_read() - -<tt/int comedi_dio_read(comedi_t *it,unsigned int subd,unsigned int -chan,unsigned int *bit);/ - - -The function reads the status of channel <tt/chan/ belonging to the digital -input subdevice <tt/subd/ of device <tt/it/. The result, 0 or 1, is stored -in bit. Returns -1 on failure. - - -This function is equivalent to <tt/comedi_data_read(it,subd,chan,0,0,bit)/. - - -Source: <tt>/lib/dio.c</tt> - - -<sect2>comedi_dio_write() - -<tt/int comedi_dio_write(comedi_t *it,unsigned int subd,unsigned -int chan,unsigned int bit);/ - - -The function writes the value of <tt/bit/, 0 or 1, to channel <tt/chan/, -belonging to the digital output device <tt/subd/ of device <tt/it/. Returns --1 on failure. - - -Source: <tt>/lib/dio.c</tt> - - -<sect2>comedi_fileno() - - -<tt/int comedi_fileno(comedi_t *it);/ - - -The function <tt/comedi_fileno/ -returns the integer descriptor for the handle <tt/it/. It -is equivalent to the standard function <tt/fileno/. If -<tt>it</tt> is an invalid <tt>comedi_t</tt> pointer, the function -returns -1 and sets the appropriate libcomedi error value. - -Source: <tt>/lib/comedi.c</tt> - - - -<sect2>comedi_find_range() - - -<tt/int comedi_find_range(comedi_t *it, unsigned int subdevice, unsigned -int chan, unsigned int unit, double min, double max);/ - - -The function <tt/comedi_find_range/ tries to -locate the optimal (smallest) range for the channel <tt>chan</tt> -belonging to a <tt>subdevice</tt> of the comedi device <tt>it</tt>, -that includes both <tt>min</tt> and <tt>max</tt> in <tt>units</tt>. -If it finds a matching range, it returns its index. If no -matching range is available, it returns -1. - - -Valid units are: - -<itemize> -<item>UNIT_volt -<item>UNIT_mA -<item>UNIT_none -</itemize> - -Source: <tt>/lib/range.c</tt> - - - -<sect2>comedi_errno() -<label id="comedi_errno"> - -<tt/int comedi_errno(void);/ - - -The function <tt>comedi_errno()</tt> -returns an integer describing the most recent comedilib error. This -integer may be used as the <tt>errnum</tt> parameter for -<tt><ref id="comedi_strerror" name ="comedi_strerror()"></tt>. - -When a libcomedi function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -<tt>comedi_errno()</tt>. This error number can be -converted to a human-readable form by the functions -<tt><ref id="comedi_perror" name ="comedi_perror()"></tt> - and <tt><ref id="comedi_strerror" name ="comedi_strerror()"></tt>. - -These functions are intended to mimic the behavior of the -standard C library functions <tt>perror()</tt>, -<tt>strerror</tt>, and <tt>errno()</tt>. In particular, -libcomedi functions sometimes return an error that is generated -by the C library; the Comedi error message in this case -is the same as the C library. - -Source: <tt>/lib/error.c</tt> - - - -<sect2>comedi_find_subdevice_by_type() - - -<tt>int comedi_find_subdevice_by_type(comedi_t *it,int type,unsigned int -start_subdevice);</tt> - - -The function <tt>comedi_find_subdevice_by_type</tt> tries to -locate a subdevice belonging to comedi device <tt>it</tt>, -having type <tt>type</tt>, starting with the subdevice -<tt>start_subdevice</tt>. If it finds the requested subdevice, -it returns its index. If it does not locate the requested -subdevice, it returns -1 and sets the comedi error number to -"subdevice not found". If there is an error, the function -returns -1 and sets the appropriate error. - - -For subdevice types, see the manual page for the function -<tt><ref id="comedi_get_subdevice_type" name = -"comedi_get_subdevice_type()"></tt>. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_from_phys()<label id="comedi_from_phys"> - - -<tt/lsampl_t comedi_from_phys(double data, comedi_range *rng, -lsampl_t maxdata);/ - -Converts data given in physical units (<tt/data/) into sample values -(lsampl_t, between 0 and maxdata). The parameter <tt>rng</tt> -represents the conversion information to use, and the parameter -<tt>maxdata</tt> represents the maximum possible data value for the -channel that the data will be written to. - - -Source: <tt>/lib/range.c</tt> - - - -<sect2>comedi_get_board_name() - - -<tt/char *comedi_get_board_name(comedi_t *it);/ - -The function <tt/comedi_get_board_name/ returns a pointer -to a string containing the name of the device. This pointer is -valid until the comedi descriptor <tt/it/ is closed. This -function returns <tt/NULL/ if there is an error. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_get_driver_name() - - -<tt/char *comedi_get_driver_name(comedi_t *it);/ - -The function <tt/comedi_get_driver_name/ returns a pointer -to a string containing the name of the driver being used by comedi -for the comedi device represented by <tt/it/. This pointer is -valid until the comedi descriptor <tt/it/ is closed. This -function returns <tt/NULL/ if there is an error. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_get_maxdata() - - -<tt/lsampl_t comedi_get_maxdata(comedi_t *it,unsigned int -subdevice,unsigned int chan);/ - - -The function <tt/comedi_get_maxdata()/ returns the maximum -valid data value for channel <tt/chan/ of subdevice -<tt/subdevice/ belonging to the comedi device <tt/it/ -This function returns 0 on error. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_get_n_channels() - - -<tt/int comedi_get_n_channels(comedi_t *it,unsigned int subdevice);/ - -The function <tt>comedi_get_n_channels()</tt> returns the number -of channels of the subdevice belonging to the comedi device <tt>it</tt> -and having index <tt>subdevice</tt>. This function returns -1 on error. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_get_n_ranges() - - -<tt>int comedi_get_n_ranges(comedi_t *it,unsigned int subdevice, unsigned int -chan);</tt> - -The function <tt>comedi_get_n_ranges()</tt> returns the number -of ranges of the channel <tt>chan</tt> belonging to the <tt>subdevice</tt> -of the comedi device <tt>it</tt>. This function returns -1 on error. - -Source: <tt>/lib/range.c</tt> - - - -<sect2>comedi_get_n_subdevices() - - -<tt>int comedi_get_n_subdevices(comedi_t *it);</tt> - -The function <tt>comedi_get_n_subdevices</tt> returns the -number of subdevices associated with the comedi descriptor -<tt>it</tt>, or -1 if there is an error. - -Source: <tt>/lib/get.c</tt> - - - -<sect2>comedi_get_range() - - -<tt>comedi_range * comedi_get_range(comedi_t *it,unsigned int subdevice,unsigned int chan,unsigned int -range);</tt> - -The function <tt>comedi_get_range</tt> returns a pointer to a -comedi_range structure that contains information that can be used to -convert sample values to or from physical units. The pointer is valid -until the comedi device <tt>it</tt> is closed. If there is an -error, NULL is returned. - -Source: <tt>/lib/get.c</tt> - - -<sect2>comedi_get_rangetype() <it/deprecated/ - - -<tt>int comedi_get_rangetype(comedi_t *it,unsigned int subdevice,unsigned int -chan);</tt> - -The function <tt>comedi_get_rangetype()</tt> returns an integer -that represents the number of range specifications available for a -particular channel <tt/chan/ of the subdevice <tt/subdevice/, as well as a conversion table to convert sample -values to/from physical units. - - The macro -<tt>RANGE_LENGTH(rangetype)</tt> -can be used to determine the number of range specifications for a given -range type. - - -This function is deprecated and should not be used in new code. - -Source: <tt>/lib/get.c</tt> - - -<sect2>comedi_get_subdevice_type()<label id="comedi_get_subdevice_type"> - - -<tt>int comedi_get_subdevice_type(comedi_t *it,unsigned int subdevice);</tt> - -The function <tt>comedi_get_subdevice_type()</tt> returns an -integer describing the type of subdevice that belongs to the comedi -device <tt>it</tt> and has the index <tt>subdevice</tt>. The -function returns -1 is there is an error. - -Valid subdevice types are: - -<itemize> -<item><tt>COMEDI_SUBD_UNUSED</tt> -Subdevice has no functionality, i.e., a place-holder. -<item><tt>COMEDI_SUBD_AI</tt> Analog input -<item><tt>COMEDI_SUBD_AO</tt> Analog output -<item><tt>COMEDI_SUBD_DI</tt> Digital input -<item><tt>COMEDI_SUBD_DO</tt> Digital output -<item><tt>COMEDI_SUBD_DIO</tt> -Digital input/output. Channels are configurable as to whether they -are inputs or outputs. -<item><tt>COMEDI_SUBD_COUNTER</tt> Counter -<item><tt>COMEDI_SUBD_TIMER</tt> Timer -<item><tt>COMEDI_SUBD_MEMORY</tt> -Memory, e.g., EEPROM or dual-ported RAM -<item><tt>COMEDI_SUBD_CALIB</tt> -Calibration DACs -<item><tt>COMEDI_SUBD_PROC</tt> -Processor or DSP -</itemize> - -Source: <tt>/lib/get.c</tt> - - -<sect2>comedi_get_timer() <it/(deprecated)/ - - -<tt/int comedi_get_timer(comedi_t *it,unsigned int subdev, double -freq,unsigned int *trigvar, double *actual_freq);/ - - -The function <tt>comedi_get_timer</tt> converts the frequency <tt/freq/ -to a number suitable to send to the driver in a <tt/comedi_trig/ -structure. This function remains for compatibility with very -old versions of Comedi, that converted sampling rates to timer -values in the libary. This conversion is now done in the kernel, -and every device has the timer type <tt/nanosec_timer/, indicating -that timer values are simply a time specified in nanoseconds. - - -This function is deprecated and should not be used in new applications. - - -Source: <tt>/lib/timer.c</tt> - - -<sect2>comedi_get_version_code() - - -<tt/int comedi_get_version_code(comedi_t *it);/ - - -The function <tt/comedi_get_version_code()/ returns the -version code of the currently running comedi module. The version -code is of the form 0x01072b, which is the version code for -version 1.7.43. - - -This function is of limited usefulness. A typical mis-application -of this function is to use it to determine if a certain feature is -supported. If the application needs -to know of the existence of a particular feature, an existence -test function should be written and put in the libcomedi source. - -Source: <tt>/lib/get.c</tt> - - -<sect2>comedi_loglevel() - - -<tt>int comedi_loglevel(int loglevel);</tt> - - -This function affects the output of debugging and error messages -from libcomedi. By increasing the loglevel, additional debugging -information will be printed. This function returns the previous -loglevel. Error messages and debugging are printed to the -stream <tt/stderr/. The loglevel can also be affected by the -environment variable COMEDI_LOGLEVEL. - - -In order to conserve resources, some debugging information is -disabled when libcomedi is compiled. - -The meaning of the loglevels is as follows: - -<itemize> -<item><tt/COMEDILIB_LOGLEVEL=0/ - -Comedilib prints nothing. - -<item><tt/COMEDILIB_LOGLEVEL=1/ (default) - -Comedilib only prints error messages when there is a -self-consistency error (i.e., internal bug). - -<item><tt/COMEDILIB_LOGLEVEL=2/ - -Comedilib prints an error message when an invalid -parameter is passed to comedilib. - -<item><tt/COMEDILIB_LOGLEVEL=3/ - -Comedilib prints an error message whenever an error is generated -in the comedilib library or is generated in the C library when -called by comedilib. - -<item><tt/COMEDILIB_LOGLEVEL=4/ - -Comedilib prints a lot of debugging messages. - -</itemize> - -Bugs: Libcomedi doesn't currently have much debugging information. - -Source: <tt>/lib/error.c</tt> - - -<sect2>comedi_open() - - -<tt/comedi_t *comedi_open(char *filename);/ - -Opens a comedi device specified by the filename <tt/filename/. -Returns NULL on error. On sucess, it returns a handle that is -given as a parameter to other libcomedi functions. - - -You are not supposed to have access to the internals of the -<tt/comedi_t/ structure. - -Bugs: Not strictly identical to <tt/fopen/ - -Source: <tt>/lib/comedi.c</tt> - - - -<sect2>comedi_perror()<label id="comedi_perror"> - - -<tt>void comedi_perror(const char *s);</tt> - -When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -<tt><ref id="comedi_errno" name ="comedi_errno()"></tt>. - This error number can be - converted to a human-readable form by the functions -<tt>comedi_perror()</tt> - and <tt><ref id="comedi_strerror" name ="comedi_strerror()"></tt>. - -These functions are intended to mimic the behavior of the -standard C library functions <tt>perror()</tt>, -<tt>strerror</tt>, and <tt>errno()</tt>. In particular, -comedilib functions sometimes return an error that is generated -inside the C library; the comedi error message in this case -is the same as the C library. - -The function <tt>comedi_perror()</tt> prints an error -message to stderr. The error message consists of the -argument string, a colon, a space, a description of the error -condition, and a new line. - -Bugs: Does not support internationalization. - -Source: <tt>/lib/error.c</tt> - - - -<sect2>comedi_strerror()<label id="comedi_strerror"> - - -<tt>*comedi_strerror(int errnum);</tt> - -When a comedilib function fails, it usually returns -1 or -NULL, depending on the return type. An internal library -variable stores an error number, which can be retrieved with -<tt><ref id="comedi_errno" name ="comedi_errno()"></tt>. This error number can be -converted to a human-readable form by the functions -<tt><ref id="comedi_perror" name ="comedi_perror()"></tt> - and <tt>comedi_strerror()</tt>. - -These functions are intended to mimic the behavior of the -standard C library functions <tt>perror()</tt>, -<tt>strerror</tt>, and <tt>errno()</tt>. In particular, -comedilib functions sometimes return an error that is generated -inside the C library; the comedi error message in this case -is the same as the C library. - -The function <tt>comedi_strerror()</tt> returns a pointer to a -character string -describing the comedilib error <tt>errnum</tt>. The persistence -of the returned pointer is undefined, and should not be trusted -after the next libcomedi call. An unrecognized error number will -return a pointer to the string "undefined error", or similar. - -Bugs: Does not support internationalization. - -Source: <tt>/lib/error.c</tt> - - - -<sect2>comedi_sv_init() - - -<tt/int comedi_sv_init(comedi_sv_t *sv,comedi_t *dev,unsigned int subd, -unsigned int chan);/ - - -<tt/comedi_sv_init/ initializes the slow varying comedi structure -<tt/sv/ of the device <tt/dev/, the subdevice <tt/subd/ (analog input) and -the channel <tt/chan/. -The slow varying comedi structure <tt/sv/ of type <tt><ref id="comedi_sv_t" -name="comedi_sv_t"</tt> -specifies the signal measurement. The default number of averaged -samples is 100. Returns zero on success, -1 on error. - -Bugs: comedi_sv_* was very poorly designed. - -Source: <tt>/lib/sv.c</tt> - - - -<sect2>comedi_sv_update() - - -<tt/int comedi_sv_update(comedi_sv_t *sv);/ - -The function <tt/comedi_sv_update/ updates the slow varying comedi structure -<tt/sv/. -Returns zero on success, -1 on error. - -Source: <tt>/lib/sv.c</tt> - - - -<sect2>int comedi_sv_measure() - - -<tt>int comedi_sv_measure(comedi_sv_t *it,double *data);</tt> - -<tt/comedi_sv_measure/ measures the slow variing signal. The measurement -is specified by the slow varying comedi structure <tt/sv/, the result is -stored in <tt/data/. -On success returns the number of samples, -1 on error. - -Source: <tt>/lib/sv.c</tt> - - - -<sect2>comedi_to_phys()<label id="comedi_to_phys"> - - -<tt/double comedi_to_phys(lsampl_t data, comedi_range *rng, -lsampl_t maxdata);/ - -Converts data given in sample values (lsampl_t, between 0 and -maxdata) into physical units (double). The parameter <tt/rng/ -represents the conversion information to use, and the parameter -<tt/maxdata/ represents the maximum possible data value for the -channel that the data was read. - -Source: <tt>/lib/range.c</tt> - - - -<sect2>comedi_trigger() <it/(deprecated)/ - - -<tt/int comedi_trigger(comedi_t *it,comedi_trig *trig);/ - -The function <tt/comedi_trigger/ instructs comedi to -perform the command specified by the <ref id="comedi_trig_struct" name -="trigger structure"> <tt/trig/. Results depend on -the particular command being issued. If there is an -error, -1 is returned. - -Lifetime: removal at 1.0. - -Source: <tt>/lib/comedi.c</tt> - - - -<sect2>comedi_get_subdevice_flags() -<label id="comedi_get_subdevice_flags"> - - -<tt/int comedi_get_subdevice_flags(comedi_t *dev, unsigned int subdevice);/ - - -This function returns a bitfield describing the capabilities of the -specified subdevice. If there is an error, -1 is returned. - -The bits are: - -<itemize> -<item>SDF_BUSY subdevice is running a command -<item>SDF_BUSY_OWNER subdevice is running a command started by -the file descriptor used by <tt/dev/. -<item>SDF_LOCKED subdevice is locked -<item>SDF_LOCKED_OWNER subdevice is locked by the file descriptor used -by <tt/dev/. -<item>SDF_MAXDATA maximum data values are channel dependent -<item>SDF_FLAGS channel flags are channel dependent -<item>SDF_RANGETYPE range types are channel dependent -<item>SDF_MODE0 deprecated -<item>SDF_MODE1 deprecated -<item>SDF_MODE2 deprecated -<item>SDF_MODE3 deprecated -<item>SDF_MODE4 deprecated -<item>SDF_CMD subdevice supports commands -<item>SDF_READABLE subdevice can be read from -<item>SDF_WRITEABLE subdevice can be written to -<item>SDF_RT deprecated -<item>SDF_GROUND subdevice is capable of ground analog reference -<item>SDF_COMMON subdevice is capable of common analog reference -<item>SDF_DIFF subdevice is capable of differential analog reference -<item>SDF_OTHER subdevice is capable of other analog reference -<item>SDF_DITHER subdevice recognizes dither flag -<item>SDF_DEGLITCH subdevice recognizes deglitch flag -<item>SDF_MMAP deprecated -<item>SDF_RUNNING subdevice is acquiring data (i.e., command has not -completed) -<item>SDF_LSAMPL subdevice uses samples of type lsampl_t (otherwise -sampl_t) -<item>SDF_PACKED subdevice uses bitfield samples (otherwise it uses -one sample per channel) -</itemize> - - - - -The bit definitions are part of the Comedi kernel interface. - - - -<sect2>comedi_range_is_chan_specific() -<label id="comedi_range_is_chan_specific"> - - -<tt/int comedi_range_is_chan_specific(comedi_t *dev,unsigned int subdevice);/ - - -If each channel of the specified subdevice has a different range -specification, this function returns 1. Otherwise, this function -returns 0. On error, this function returns -1. - - - -<sect2>Undocumented functions -<label id="undocumented"> - - - -<itemize> -<item>comedi_maxdata_is_chan_specific() -<item>comedi_get_buffer_size() -<item>comedi_get_max_buffer_size() -<item>comedi_set_buffer_size() -<item>comedi_set_max_buffer_size() -<item>comedi_do_insnlist() -<item>comedi_do_insn() -<item>comedi_lock() -<item>comedi_unlock() -<item>comedi_get_cmd_src_mask() -<item>comedi_get_cmd_generic_timed() -<item>comedi_cancel() -<item>comedi_command() -<item>comedi_command_test() -<item>comedi_poll() -<item>comedi_get_buffer_contents() -<item>comedi_mark_buffer_read() -<item>comedi_get_buffer_offset() -<item>comedi_set_global_oor_behavior() -</itemize> - - - - - - - - - - -</article> -

6.1 Constants and Macros +

CR_PACK(channel, range, aref)

RANGE_LENGTH() (deprecated)

6.2 Data Types and Structures +

comedi_t

sampl_t

lsampl_t

comedi_trig_struct (deprecated)

comedi_sv_t

6.1 comedi_loglevel() -

6.2 comedi_open -

6.3 comedi_fileno() -

6.4 comedi_get_n_subdevices() -

comedi_cmd

6.5 comedi_get_version_code() -

6.6 comedi_get_driver_name() -

6.7 comedi_get_board_name() -

6.8 comedi_get_subdevice_type() -

6.9 comedi_find_subdevice_by_type() -

6.10 comedi_get_n_channels() -

comedi_insn

6.11 comedi_get_maxdata() -

6.12 comedi_get_rangetype() -

6.13 comedi_get_range() -

6.14 comedi_trigger() -

6.15 comedi_data_read() + + +

comedi_range

comedi_close()

comedi_command()

comedi_command_test()

comedi_data_read()

comedi_data_write()

6.16 comedi_sv_init() -

6.17 comedi_get_timer() -

comedi_dio_bitfield();

comedi_dio_config()

comedi_dio_read()

comedi_dio_write()

comedi_fileno()

comedi_find_range()

comedi_errno()

comedi_find_subdevice_by_type()

comedi_from_phys()

comedi_get_board_name()

comedi_get_cmd_src_mask()

comedi_get_driver_name()

comedi_get_maxdata()

comedi_get_n_channels()

comedi_get_n_ranges()

comedi_get_n_subdevices()

comedi_get_range()

comedi_get_rangetype() deprecated

comedi_get_subdevice_type()

comedi_get_timer() (deprecated)

comedi_get_version_code()

comedi_loglevel()

comedi_open()

comedi_perror()

comedi_strerror()

comedi_sv_init()

comedi_sv_update()

int comedi_sv_measure()

comedi_to_phys()

comedi_trigger() (deprecated)

comedi_get_subdevice_flags()

comedi_range_is_chan_specific()

Undocumented functions

Comedi Documentation

David Schleef, ds@stm.lbl.gov

David Schleef ds@stm.lbl.gov, +Frank Hess fmhess@uiuc.edu

1.1 Constants and Macros -

RANGE_LENGTH() (deprecated)

1.2 Data Types and Structures -

comedi_t

sampl_t

lsampl_t

comedi_trig_struct (deprecated)

comedi_sv_t

comedi_cmd

comedi_insn

David Schleef, `ds@stm.lbl.gov`

David Schleef `ds@stm.lbl.gov`, +Frank Hess `fmhess@uiuc.edu`