Hi,
the function below ist running for hours but sometimes an error no 9
occours (which must be "Bad File Number*"). *Does anyone have an idea or
suggestions for other flags? This is the only function in the whole
programm that is accessing the ADC. After the exit systemd restarts the
programm and it runs fine again for hours. The function is called from a
loop while another file with another fd is open (logfile for the adc-data,
with a size of about 500bytes then a new logfile is started). The
read_raw_adc_ch(0); is called every 10 seconds. As you can see I've tried
to write a workaround with the error_ctr loop, but even the wait for one
second does not help.
Thanks for any ideas or suggestions.
Alex
$ cat /proc/version
Linux version 4.19.94-ti-r42 (voodoo@x3-am57xx-beagle-x15-2gb) (gcc version
8.3.0 (Debian 8.3.0-6)) #1buster SMP PREEMPT Tue Mar 31 19:38:29 UTC 2020
cat /etc/debian_version
10.3
Board: BeagleBoneBlack Rev. C
------------------------------------------------------------------------------------------------------------------------------------
uint16_t read_raw_adc_ch(int channel)
{
uint8_t error_ctr;
char str[MAX_BUF];
int output_fd;
extern int errno;
error_ctr = 0;
while (error_ctr < 8)
{
// oeffnen loest eine messung des adc aus
if (channel==0) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage0_raw", O_RDONLY |
O_ASYNC);
if (channel==1) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage1_raw", O_RDONLY |
O_ASYNC);
if (channel==2) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage2_raw", O_RDONLY |
O_ASYNC);
if (channel==3) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage3_raw", O_RDONLY |
O_ASYNC);
if (channel==4) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage4_raw", O_RDONLY |
O_ASYNC);
if (channel==5) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage5_raw", O_RDONLY |
O_ASYNC);
if (channel==6) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage6_raw", O_RDONLY |
O_ASYNC);
if (channel==7) output_fd =
open("/sys/bus/iio/devices/iio:device0/in_voltage7_raw", O_RDONLY |
O_ASYNC);
if (output_fd < 0)
{
error_ctr++;
close(output_fd);
sleep(1);
}
else
{
read(output_fd, str, 10);
close(output_fd);
return atoi(str);
}
}
printf("ERROR OPEN ADC DEVICE, ERRNO: %d", errno);
exit(EXIT_FAILURE);
return 0;
}
------------------------------------------------------------------------------------------------------------------------------------
--
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