- From: L.C. Karssen <l.c.karssen_at_phys.uu.nl>
- Date: Mon, 21 May 2007 09:42:25 +0000
On Sun, 2007-05-13 at 23:37 +0200, Paolo Mantegazza wrote:
> L.C. Karssen writes:
>
> > Hi list,
> >
> > Excuse me for sending this message to both the Comedi and the RTAI list,
> > but I'm not sure where the problem is.
> >
> > I'm trying to control an NI-DAQ PCI-6024E card with comedi and RTAI.
> > I'm running RTAI in periodic mode.
> You are using too an old RTAI version. You should upgrade, so you'll get a
> first warning esplicitely, with the syscall number, following if it is just
> a first episode or it continues afterward by checking the related count
> using proc/rtai/scheduler.
I did a fresh install of Slackware 11.0 with RTAI 3.5 and comedi CVS of
May 14th (it says 0.7.73 when loading the modules). I followed the
instructions on installling RTAI and comedi from the RTAI-Lab tutorial.
When I run my program now I get the following dmesg entry:
LXRT CHANGED MODE (SYSCALL), PID = 8122, SYSCALL = 54.
>
> In any case if it is signalled so it happened for sure, i.e. your code
> called Linux after being made hard real time.
Below is the function in my program that does the RT work. After going
to hard real time I basically only use comedi_dio_bitfield() and
comedi_do_insn() to clock out bits that are stored in an array of
structs. After writing one set of bits to DIO and both AO's the program
should wait for the period (typically ~15us) and then clock out the next
entry in the array. I don't see where I make a Linux system call (but
I'm not 100% what a system call is).
Any help is appreciated!
Lennart.
int do_comedi(struct data_struct *options)
{
comedi_t *comedi_dev = options->device;
unsigned int ao_subdev = options->AO_subdevice; // Analog Output
unsigned int dio_subdev = options-> DIO_subdevice; // Digital IO
int range=0; // AO has only one range: 10V -> -10V
comedi_insn insn;
lsampl_t data;
unsigned int dio_bits;
int aref = AREF_GROUND;
unsigned int dio_mask = 0xFFFFFFFF; // Tells which DIO bits are to
be flipped (all).
int period;
struct bits *data_arr = options->bitsarr;
RT_TASK* task;
int priority=0;
int stack_size=4096;
int msg_size=0;
int i;
/* Prepare the AO instruction as much as possible. Later, in real
time
* we'll only fill in the data sample. */
insn.insn = INSN_WRITE;
insn.n = 1;
insn.subdev = ao_subdev;
/* A better scheduler than linux' one */
struct sched_param mysched;
/* We don't want to be swapped out the mem */
mlockall (MCL_CURRENT | MCL_FUTURE);
/* Allow nonroot users hard realtime access */
rt_allow_nonroot_hrt();
/* Initialise Scheduler as SCHED_FIFO. Greatly improves scheduler!
*/
mysched.sched_priority = sched_get_priority_max(SCHED_FIFO) - 1;
if( sched_setscheduler( 0, SCHED_FIFO, &mysched ) == -1 )
{
fprintf(stderr, "Error in setting the Scheduler!\n");
exit(1);
}
/* Register this thread as a RT task. As long as it's
not switched to hard_real_time, it's still a normal process and
can do all normal things */
task = rt_task_init(nam2num("do_comedi"), priority, stack_size,
msg_size);
// Set mode to periodic. Other option is 'oneshot'
rt_set_periodic_mode();
period = (int) nano2count((RTIME)options->period*1000);
start_rt_timer(period);
// Switch to hard realtime mode
rt_make_hard_real_time();
// Start scheduler
rt_task_make_periodic(task, rt_get_time() + period, period);
for (i=0; i<options->n_rows; i++)
{
/* Prepare and write digital data. */
dio_bits = data_arr[i].DIO;
comedi_dio_bitfield(comedi_dev, dio_subdev, dio_mask, &dio_bits);
/* Prepare and write AO data */
data = data_arr[i].AO0;
insn.data = &data;
insn.chanspec = CR_PACK(0, range, aref);
if(comedi_do_insn(comedi_dev, &insn)<0)
{
comedi_perror("/dev/comedi0");
exit(1);
}
data = data_arr[i].AO1;
insn.data = &data;
insn.chanspec = CR_PACK(1, range, aref);
if(comedi_do_insn(comedi_dev, &insn)<0)
{
comedi_perror("/dev/comedi0");
exit(1);
}
rt_task_wait_period();
}
rt_make_soft_real_time();
#ifdef DEBUG
printf("We're back in soft realtime.\n");
#endif
// Stop timer
stop_rt_timer();
// Unregister RT task
rt_task_delete(task);
// Unlock mem
munlockall();
return 0;
}
>
> Paolo.
>
> > Lennart.
> > --
> > *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
> > L.C. Karssen
> > Department of Physics and Astronomy
> > Faculty of Science
> > Utrecht University
> > Princetonplein 1
> > 3584 CC Utrecht
> > The Netherlands
> >
> > tel.: +31 (0)30-253-2208
> > fax.: +31 (0)30-253-7468
> > e-mail: L.C.Karssen_at_phys.uu.nl
> > www: http://www1.phys.uu.nl/wwwaoud
> > -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
> >
> >
> > _______________________________________________
> > RTAI mailing list
> > RTAI_at_rtai.org
> > https://mail.rtai.org/cgi-bin/mailman/listinfo/rtai
>
--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
L.C. Karssen
Department of Physics and Astronomy
Faculty of Science
Utrecht University
Princetonplein 1
3584 CC Utrecht
The Netherlands
tel.: +31 (0)30-253-2208
fax.: +31 (0)30-253-7468
e-mail: L.C.Karssen_at_phys.uu.nl
www: http://www1.phys.uu.nl/wwwaoud
-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
Received on 2007-05-21Z08:42:25