From: Frank Mori Hess Date: Tue, 12 Feb 2008 19:31:26 +0000 (+0000) Subject: Updated the dio function reference X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=7eb7a64566cb87b765a5baebfc2b824e54f626e7;p=comedilib.git Updated the dio function reference --- diff --git a/doc/dio_funcref.txt b/doc/dio_funcref.txt index 5a69f53..fc7ef26 100644 --- a/doc/dio_funcref.txt +++ b/doc/dio_funcref.txt @@ -22,9 +22,9 @@ Description: reading an output channel is the last value written to the output channel. - All the channels may not be read or written at the exact same time. + All the channels might not be read or written at the exact same time. For example, the driver may need to sequentially write to - several ports in order to set all the digital channels specified + several registers in order to set all the digital channels specified by the write_mask. Function: comedi_dio_config -- change input/output properties of channel @@ -36,15 +36,16 @@ Param: unsigned int direction Description: 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 direction. Valid directions are + on the value of direction. Valid directions are COMEDI_INPUT or COMEDI_OUTPUT. - Depending on the capabilities of the hardware device, multiple - channels may be grouped together to determine direction. In this + Depending on the characteristics of the hardware device, multiple + channels might be grouped together in hardware when + configuring the input/output direction. In this case, a single call to comedi_dio_config() for any channel in the group will affect the entire group. - - If successful, 1 is returned, otherwise -1. +Returns: + If successful, 0 is returned, otherwise -1. Function: comedi_dio_get_config -- query input/output properties of channel Retval: int @@ -53,12 +54,13 @@ Param: unsigned int subdevice Param: unsigned int channel Param: unsigned int * direction Description: - The function comedi_dio_get_config() querys the configuration of + The function comedi_dio_get_config() querys the input/output configuration of an individual channel - in a digital I/O subdevice (see comedi_dio_config()). - On success, the variable specified by the "direction" pointer will + in a digital I/O subdevice (see + comedi_dio_config). + On success, *direction will be set to either COMEDI_INPUT or COMEDI_OUTPUT. - +Returns: If successful, 0 is returned, otherwise -1. Function: comedi_dio_read -- read single bit from digital channel @@ -68,14 +70,25 @@ Param: unsigned int subdevice Param: unsigned int channel Param: unsigned int * bit Description: - The function reads the channel channel belonging to the - subdevice subdevice of device device. The data value that is - read is stored in the location pointed to by bit. This function - is equivalent to comedi_data_read(device,subdevice,channel,0,0,bit). + The function comedi_dio_read reads the channel channel + belonging to the + subdevice subdevice of device device. + The data value that is + read is stored in the *bit. This function + is equivalent to: + + comedi_data_read(device, subdevice, channel, 0, 0, bit); + This function does not require a digital subdevice or a subdevice with a maximum data value of 1 to work properly. - Return values and errors are the same as comedi_data_read(). + If you wish to read multiple digital channels at once, it is more efficient to + use + comedi_dio_bitfield2 + than to call this function multiple times. +Returns: + Return values and errors are the same as + comedi_data_read. Function: comedi_dio_write -- write single bit to digital channel Retval: int @@ -84,10 +97,21 @@ Param: unsigned int subdevice Param: unsigned int channel Param: unsigned int bit Description: - The function writes the value bit to the channel channel belonging - to the subdevice subdevice of device device. This function - is equivalent to comedi_data_write(device,subdevice,channel,0,0,bit). + The function writes the value bit to the channel + channel belonging + to the subdevice subdevice of device + device. This function + is equivalent to: + + comedi_data_write(device, subdevice, channel, 0, 0, bit); + This function does not require a digital subdevice or a subdevice with a maximum data value of 1 to work properly. - Return values and errors are the same as comedi_data_write(). + If you wish to write multiple digital channels at once, it is more efficient to + use + comedi_dio_bitfield2 + than to call this function multiple times. +Returns: + Return values and errors are the same as + comedi_data_write.