added square wave generation on channel 1, made scans with more than one channel

work, added 5 volt range, added documentation comments

diff --git a/comedi/drivers/dummy_waveform.c b/comedi/drivers/dummy_waveform.c
index 000d8c66780ee66a06bb9de58b5e75dba73dc7f4..af933068f1e62aae9833e361cd7b7548d904fbc2 100644 (file)
--- a/comedi/drivers/dummy_waveform.c
+++ b/comedi/drivers/dummy_waveform.c
@@ -27,6 +27,23 @@
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
 ************************************************************************/
+/*
+Driver: dummy_waveform.o
+Description: generates fake waveforms
+Authors: Joachim Wuttke <Joachim.Wuttke@icn.siemens.de>, Frank Mori Hess <fmhess@uiuc.edu>
+Devices:
+Status: works
+Updated: 2002-03-05
+
+Configuration options:
+  [0] - Amplitude in microvolts for fake waveforms (default 1 volt)
+  [1] - Period in microseconds for fake waveforms (default 0.1 sec)
+
+Generates a sawtooth wave on channel 0, square wave on channel 1, additional
+waveforms could be added to other channels (currently they return flatline
+zero volts).
+
+*/
 
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -86,7 +103,22 @@ static int waveform_ai_cmdtest(comedi_device *dev,comedi_subdevice *s,
 static int waveform_ai_cmd(comedi_device *dev, comedi_subdevice *s);
 static int waveform_ai_cancel(comedi_device *dev, comedi_subdevice *s);
 static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data);
-static sampl_t fake_sawtooth(comedi_device *dev, unsigned long current_time);
+static sampl_t fake_sawtooth(comedi_device *dev, unsigned int range, unsigned long current_time);
+static sampl_t fake_squarewave(comedi_device *dev, unsigned int range, unsigned long current_time);
+static sampl_t fake_flatline(comedi_device *dev, unsigned int range, unsigned long current_time);
+static sampl_t fake_waveform(comedi_device *dev, unsigned int channel,
+       unsigned int range, unsigned long current_time);
+
+// fake analog input ranges
+static comedi_lrange waveform_ai_ranges =
+{
+       2,
+       {
+               BIP_RANGE(10),
+               BIP_RANGE(5),
+       }
+};
+
 /*
    This is the background routine used to generate arbitrary data.
    It should run in the background; therefore it is scheduled by
@@ -97,7 +129,7 @@ void waveform_ai_interrupt(unsigned long arg)
        comedi_device *dev = (comedi_device*) arg;
        comedi_async *async = dev->read_subdev->async;
        comedi_cmd *cmd = &async->cmd;
-       unsigned long i;
+       unsigned int i, j;
        // all times in microsec
        unsigned long elapsed_time;
        unsigned int num_scans;
@@ -115,8 +147,12 @@ void waveform_ai_interrupt(unsigned long arg)
 
        for(i = 0; i < num_scans; i++)
        {
-               comedi_buf_put(async,
-                       fake_sawtooth(dev, devpriv->usec_current + i * scan_period));
+               for( j = 0; j < cmd->chanlist_len; j++)
+               {
+                       comedi_buf_put(async,
+                               fake_waveform(dev, CR_CHAN(cmd->chanlist[j]), CR_RANGE(cmd->chanlist[j]),
+                                       devpriv->usec_current + i * scan_period));
+               }
                devpriv->ai_count++;
                if(cmd->stop_src == TRIG_COUNT && devpriv->ai_count >= cmd->stop_arg)
                {
@@ -169,7 +205,7 @@ static int waveform_attach(comedi_device *dev,comedi_devconfig *it)
        s->subdev_flags = SDF_READABLE | SDF_GROUND;
        s->n_chan = thisboard->ai_chans;
        s->maxdata = (1 << thisboard->ai_bits) - 1;
-       s->range_table = &range_bipolar10;
+       s->range_table = &waveform_ai_ranges;
        s->len_chanlist = 16;
        s->insn_read = waveform_ai_insn_read; // apparently, we do not need waveform_ai_rinsn;
        s->do_cmd = waveform_ai_cmd;
@@ -354,27 +390,78 @@ unsigned long long my_ull_div(unsigned long long numerator, unsigned long denomi
        return value + my_ull_div(remainder, denominator);
 }
 
-static sampl_t fake_sawtooth(comedi_device *dev, unsigned long current_time)
+static sampl_t fake_sawtooth(comedi_device *dev, unsigned int range_index, unsigned long current_time)
 {
        comedi_subdevice *s = dev->read_subdev;
        unsigned int offset = s->maxdata / 2;
-       unsigned long long value = 0;
+       unsigned long long value;
+       comedi_krange *krange = &s->range_table->range[range_index];
+       unsigned long long binary_amplitude;
+
+       binary_amplitude = s->maxdata;
+       binary_amplitude *= devpriv->uvolt_amplitude;
+       binary_amplitude = my_ull_div(binary_amplitude, krange->max - krange->min);
 
        current_time %= devpriv->usec_period;
        value = current_time;
-       value *= s->maxdata;
+       value *= binary_amplitude * 2;
        value = my_ull_div(value, devpriv->usec_period);
+       value -= binary_amplitude;      // get rid of sawtooth's dc offset
+
+       return offset + value;
+}
+static sampl_t fake_squarewave(comedi_device *dev, unsigned int range_index, unsigned long current_time)
+{
+       comedi_subdevice *s = dev->read_subdev;
+       unsigned int offset = s->maxdata / 2;
+       unsigned long long value;
+       comedi_krange *krange = &s->range_table->range[range_index];
+       current_time %= devpriv->usec_period;
+
+       value = s->maxdata;
        value *= devpriv->uvolt_amplitude;
-       value = my_ull_div(value, 20000000);    // XXX
+       value = my_ull_div(value, krange->max - krange->min);
+
+       if(current_time < devpriv->usec_period / 2)
+               value *= -1;
 
        return offset + value;
 }
 
+static sampl_t fake_flatline(comedi_device *dev, unsigned int range_index, unsigned long current_time)
+{
+       return dev->read_subdev->maxdata / 2;
+}
+
+// generates a different waveform depending on what channel is read
+static sampl_t fake_waveform(comedi_device *dev, unsigned int channel,
+       unsigned int range, unsigned long current_time)
+{
+       enum
+       {
+               SAWTOOTH_CHAN,
+               SQUARE_CHAN,
+       };
+       switch(channel)
+       {
+               case SAWTOOTH_CHAN:
+                       return fake_sawtooth(dev, range, current_time);
+                       break;
+               case SQUARE_CHAN:
+                       return fake_squarewave(dev, range, current_time);
+                       break;
+               default:
+                       break;
+       }
+
+       return fake_flatline(dev, range, current_time);
+}
+
 static int waveform_ai_insn_read(comedi_device *dev, comedi_subdevice *s, comedi_insn *insn, lsampl_t *data)
 {
        int i;
        for(i = 0; i < insn->n; i++)
-               data[i] = i;
+               data[i] = s->maxdata / 2;
 
        return insn->n;
 }