High,
i am new here and have a problem with reading and writing fifos
inside a rt-task. The rt-task multiplies (at moment only this)
two values. It get this data using FIFO1, multiplying, and put the
result into the FIFO2. I get the data from the user-space into the
rt-task using FIFO1 (debug with printk .., see source rt-ss.c),
calculate and put the result into FIFO2. Inside the user-prog all
my data are destroyd after this. I dont't know why - please help me.
My code based on the frank-example.
It is possible to communicate 3 rt-task trought a fifo:
A/DU-RT-Task -> FIFO -> Controller RT-Task -> FIFO -> D/A-RT-Task ?
It's for a controller.
Thanks a lot Olaf
-----8<---- control.h ---------
#define FIFO1 0x0
#define FIFO2 0x1
#define TASK1 0x0
struct sSample {
float a;
float b;
float u;
float r;
} TestSample;
-----8<---- control.c ---------
....
int main(int argc, int **argv)
{
int fd0, fd1;
/* Open RT Pipes FIFO1 & FIFO2*/
if ((fd0 = open("/dev/rtf0", O_WRONLY)) < 0) {
perror("Error opening /dev/rtf0");
exit(errno);
}
if ((fd1 = open("/dev/rtf1", O_RDONLY)) < 0) {
perror("Error opening /dev/rtf1");
exit(errno);
}
/* Calculate in UserSpace */
printf("Multiplikation:\n");
printf("1. Zahl: ");
scanf("%f", &TestSample.a);
printf("2. Zahl: ");
scanf("%f", &TestSample.b);
TestSample.u=TestSample.a*TestSample.b;
printf("UserSpace Multiplikation: %f*%f=%f\n", TestSample.a, TestSample.b,
TestSample.u);
/* Write FIFO */
if(write(fd0, &TestSample, sizeof(TestSample)) < 0) {
perror("Can't write to fd0");
};
/* Read FIFO */
if(read(fd1, &TestSample, sizeof(TestSample)) < 0 ) {
perror("Can't read from fd1");
};
/* Print RT Calc: All values are zero */
printf("RT Multiplikation: %f*%f=%f\n", TestSample.a, TestSample.b, TestSample.r);
fflush(stdout);
}
return 0;
}
-----8<---- rt-ss.c -----------
...
#include "control.h"
...
RT_TASK mytasks[1];
...
void fun(int t)
{
while (1) {
rtf_get(FIFO1, &TestSample, sizeof(TestSample));
TestSample.r=TestSample.a*TestSample.b;
rtf_put(FIFO2, &TestSample, sizeof(TestSample));
/* All values are o.k. */
printk("Task %i: a=%i, b=%i, u=%i, r=%i\n", t,
(int)TestSample.a,
(int)TestSample.b,
(int)TestSample.u,
(int)TestSample.r);
rt_task_wait();
}
}
int init_module(void)
...
rtf_create(FIFO1, fifo_size);
rtf_create(FIFO2, fifo_size);
rt_task_init(&mytasks[TASK1], fun, data, stack_size, priority);
rt_task_use_fp(&mytasks[TASK1], 1);
rt_task_make_periodic(&mytasks[TASK1], rt_get_time(), ticks);
return 0;
}
void cleanup_module(void)
{
rtf_destroy(FIFO1);
rtf_destroy(FIFO2);
rt_task_delete(&mytasks[TASK1]);
}
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
