RE: How can I count pwm pulse's number when it is running ?

thomas he — Thu, 17 Mar 2022 01:52:56 GMT

I think the method is not the best, or the PPI with pwm can't work well. can somebody give me suggestion to implement the function?

Thanks.

RE: How can I count pwm pulse's number when it is running ?

thomas he — Tue, 15 Mar 2022 07:06:12 GMT

OK， the code for pwm and timer (work as counter mode) is below:

pwm = pwm_init();
pwm_start(pwm, 10* 1000);

printk("Counter alarm sample\n\n");
counter_dev = device_get_binding(TIMER);
if (counter_dev == NULL) {
printk("Device not found\n");
return;
}

counter_start(counter_dev);

alarm_cfg.flags = 0;
alarm_cfg.ticks = 10 * 1000;//counter_us_to_ticks(counter_dev, DELAY);
alarm_cfg.callback = test_counter_interrupt_fn;
alarm_cfg.user_data = &alarm_cfg;

err = counter_set_channel_alarm(counter_dev, ALARM_CHANNEL_ID,
&alarm_cfg);
printk("Set alarm in %u sec (%u ticks)\n",
(uint32_t)(counter_ticks_to_us(counter_dev,
alarm_cfg.ticks) / USEC_PER_SEC),
alarm_cfg.ticks);

if (-EINVAL == err) {
printk("Alarm settings invalid\n");
} else if (-ENOTSUP == err) {
printk("Alarm setting request not supported\n");
} else if (err != 0) {
printk("Error\n");
}

the pwm 's work frequency is 10k, and I can test it with oscilloscope, it work well.

the timer works as counter , I have modify the timer's driver code (.mode = NRF_TIMER_MODE_COUNTER, ) in I:\nRF\ncs\zephyr\drivers\counter\counter_nrfx_timer.c temporarily.

my prj.conf content is below:

CONFIG_PRINTK=y
CONFIG_COUNTER=y
CONFIG_GPIO=y
CONFIG_COUNTER_TIMER0=y
CONFIG_NRFX_PPI=y
CONFIG_PWM=y

thanks.

to add, pwm_start is a wrapper of pwm_pin_set_usec(....).

RE: How can I count pwm pulse's number when it is running ?

Øivind — Mon, 14 Mar 2022 14:43:09 GMT

Hi,

Could I see how you setup the PWM and timer? And your prj.conf