PC104 DAS16jr/16 buffer overrun

I have a DAS16jr/16 and am trying to make the callback feature to work
for this board. I get a callback about 55 times and read 8 channels each
time . After that i get Comedi : Buffer Overrun . If i increase the read
buffer then the number of times i get data is increases but i get the
buffer overrun after a while. Ive tried it with 1MHz and 10Mhz clock
frequencies of the Das16jr/16. Any idea where im going wrong? I dont see
why there should be a buffer overflow if im reading the buffer everytime
i get a callback. 

here is my cmd structure 
#define SAMPLE_PERIOD    40000000 
#define SAMPLE_DURATION   100000

        ai_cmd.chanlist = ai_chanspec;
        ai_cmd.chanlist_len = MAX_CHAN;
        ai_cmd.data = ai_data;
        ai_cmd.data_len = MAX_CHAN*sizeof(sampl_t);
        ai_cmd.subdev = 0;
        ai_cmd.flags = 0;
        ai_cmd.start_src = TRIG_NOW;
        ai_cmd.start_arg = 0;
        ai_cmd.scan_begin_src = TRIG_TIMER;
        ai_cmd.scan_begin_arg = SAMPLE_PERIOD;
        ai_cmd.convert_src = TRIG_TIMER;
        ai_cmd.convert_arg = SAMPLE_DURATION;
        ai_cmd.scan_end_src = TRIG_COUNT;
        ai_cmd.scan_end_arg = MAX_CHAN;
        ai_cmd.stop_src = TRIG_NONE;
        ai_cmd.stop_arg = 0;



Thanks

Muks

Received on 2003-07-30Z14:51:43