Some INSN_READ fixes for AI subdevice: enable conversion on requested

channel, munge 2's complement data to offset binary, set maxdata to 0xffff.

Also add the two reference voltage channels to the AI subdevice.

diff --git a/comedi/drivers/s526.c b/comedi/drivers/s526.c
index a1ea5c14b5300a6e841976e2ac0c3cc26f7c5f5c..332c1f0a072c7e4d7c3ffe7110d17364c64c64ef 100644 (file)
--- a/comedi/drivers/s526.c
+++ b/comedi/drivers/s526.c
@@ -340,10 +340,12 @@ static int s526_attach(comedi_device * dev, comedi_devconfig * it)
        //dev->read_subdev=s;
        /* analog input subdevice */
        s->type = COMEDI_SUBD_AI;
-       /* we support single-ended (ground) and differential */
+       /* we support differential */
        s->subdev_flags = SDF_READABLE | SDF_DIFF;
-       s->n_chan = 8;
-       s->maxdata = 0x3fff;
+       /* channels 0 to 7 are the regular differential inputs */
+       /* channel 8 is "reference 0" (+10V), channel 9 is "reference 1" (0V) */
+       s->n_chan = 10;
+       s->maxdata = 0xffff;
        s->range_table = &range_bipolar10;
        s->len_chanlist = 16;   /* This is the maximum chanlist length that
                                   the board can handle */
@@ -795,6 +797,9 @@ static int s526_ai_insn_config(comedi_device * dev, comedi_subdevice * s,
        /* data[0] : channels was set in relevant bits.
           data[1] : delay
         */
+       /* COMMENT: abbotti 2008-07-24: I don't know why you'd want to
+        * enable channels here.  The channel should be enabled in the
+        * INSN_READ handler. */
 
        // Enable ADC interrupt
        outw(ISR_ADC_DONE, ADDR_REG(REG_IER));
@@ -821,13 +826,14 @@ static int s526_ai_rinsn(comedi_device * dev, comedi_subdevice * s,
        unsigned int d;
        unsigned int status;
 
-       value = devpriv->s526_ai_config | (chan << 1);
-       // outw(value, ADDR_REG(REG_ADC)); do it with ADC start
+       /* Set configured delay, enable channel for this channel only,
+        * select "ADC read" channel, set "ADC start" bit. */
+       value = (devpriv->s526_ai_config & 0x8000) |
+               ((1 << 5) << chan) | (chan << 1) | 0x0001;
 
        /* convert n samples */
        for (n = 0; n < insn->n; n++) {
                /* trigger conversion */
-               value |= 0x0001;        // ADC start
                outw(value, ADDR_REG(REG_ADC));
 //              printk("s526: Wrote 0x%04x to ADC\n", value);
 //              printk("s526: ADC reg=0x%04x\n", inw(ADDR_REG(REG_ADC)));
@@ -853,7 +859,8 @@ static int s526_ai_rinsn(comedi_device * dev, comedi_subdevice * s,
                d = inw(ADDR_REG(REG_ADD));
 //              printk("AI[%d]=0x%04x\n", n, (unsigned short)(d & 0xFFFF));
 
-               data[n] = d;
+               /* munge data */
+               data[n] = d ^ 0x8000;
        }
 
        /* return the number of samples read/written */