Changing connection interval cause issue with PWM

RE: Changing connection interval cause issue with PWM

Hieu — Fri, 08 Jul 2016 09:42:15 GMT

Sorry for the late follow up. I was caught up with some emergent work.

Thanks Stefan. This seems to be exactly the problem and its solution. And sorry about the inconvenience about the file. I will have it fixed so people would not meet the same issue.

RE: Changing connection interval cause issue with PWM

Stefan Birnir Sverrisson — Fri, 01 Jul 2016 16:30:59 GMT

I tried your main.c file with SDK ble_app_uart example. I had to include several libraries and drivers. Could not find ir_raw.h so I just did not include that in the project. I set the duty cycle to 65% to see the pwm waveform on pin 29

while (app_pwm_channel_duty_set(&PWM, 0, 65) == NRF_ERROR_BUSY);

I also set the BLE connection timeout to 16000 ms. This is probably the cause for the invalid_parameters error. It seems that the timeout needs to be more than two times the connection interval in order to allow for at least one packet retransmit before disconnecting

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(2000, UNIT_1_25_MS)
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(3000, UNIT_1_25_MS)
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(16000, UNIT_10_MS)

On my logical analyser, the PWM period seems consistently 27us with these settings.

RE: Changing connection interval cause issue with PWM

Hieu — Tue, 28 Jun 2016 07:50:33 GMT

@stefanbirnir: I have attached the main.c that could reproduce this issue. I believe all you need to do is replace it into SDK v10's ble_app_uart and adjust MIN_CONN_INTERVAL, MAX_CONN_INTERVAL and the duty value in my pwm_init() to see different wrong waveform generated when the interval values is anywhere above 2000.

RE: Changing connection interval cause issue with PWM

Stefan Birnir Sverrisson — Mon, 27 Jun 2016 14:33:11 GMT

I can not reproduce this issue using pwm library. Perhaps you can commit your whole project.