Timer and PWM (and BLE) in nRF5 v12

RE: Timer and PWM (and BLE) in nRF5 v12

bjorn-spockeli — Wed, 13 Dec 2017 07:38:32 GMT

The SDK configuration header is documented here.

Every module in SDK contains at least one configuration option that is enabling this module. If the module is disabled, then even if source code is added to the project, it is not compiled because the module implementation is conditionally included.

RE: Timer and PWM (and BLE) in nRF5 v12

Wayne — Tue, 12 Dec 2017 18:49:58 GMT

where is it documented that you need to add APP_PWM_ENABLED ?

RE: Timer and PWM (and BLE) in nRF5 v12

paul_tanner — Mon, 31 Jul 2017 15:12:33 GMT

Please see above for answer which comes in 2 parts:

A. Starting with the timer example enable PWM and other dependencies in [board]/config/sdk_config.h

B. Configure the outer timer as above.

Many thx to @Bjorn for his assist.

RE: Timer and PWM (and BLE) in nRF5 v12

bjorn-spockeli — Mon, 31 Jul 2017 14:54:57 GMT

Setup the PWM library to use TIMER1, i.e.

APP_PWM_INSTANCE(PWM1,1);

then setup TIMER2 as the outer timer, i.e.

const nrf_drv_timer_t TIMER = NRF_DRV_TIMER_INSTANCE(2);

  nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
  err_code = nrf_drv_timer_init(&TIMER, &timer_cfg, timer_event_handler);
  APP_ERROR_CHECK(err_code);

RE: Timer and PWM (and BLE) in nRF5 v12

paul_tanner — Mon, 31 Jul 2017 14:48:21 GMT

Thx @Bjorn, that fixes the build (I also had to add the GPIOTE stuff to sdk_config.h). Is there any doc to help me understand the configuration of timers so I can have an outer timer (TIMER2) around PWM? Pls see above.

I'm thinking it could be something like:

const nrf_drv_timer_t TIMER_OUTER = NRF_DRV_TIMER_INSTANCE(2);
nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
timer_cfg.p_context=&TIMER_OUTER;  // pure guesswork and evidently WRONG!!
err_code = nrf_drv_timer_init(&TIMER_OUTER, &timer_cfg, timer_led_event_handler);

So the remaining question is how to configure this outer timer.

RE: Timer and PWM (and BLE) in nRF5 v12

bjorn-spockeli — Mon, 31 Jul 2017 13:20:43 GMT

There should be a APP_PWM section in your sdk_config.h file, i.e.

// <q> APP_PWM_ENABLED  - app_pwm - PWM functionality
 

#ifndef APP_PWM_ENABLED
#define APP_PWM_ENABLED 1
#endif

If not then you have to add it.

RE: Timer and PWM (and BLE) in nRF5 v12

paul_tanner — Mon, 31 Jul 2017 12:59:46 GMT

No mods made to sdk_config.h. That has some defines for the timers but nothing related to PWM so far as I can see. The board I am using is pca10040.

RE: Timer and PWM (and BLE) in nRF5 v12

bjorn-spockeli — Mon, 31 Jul 2017 10:51:45 GMT

Have you also modified the sdk_config.h file?

RE: Timer and PWM (and BLE) in nRF5 v12

paul_tanner — Mon, 31 Jul 2017 10:47:09 GMT

Thx @Bjorn the Makefile does contain the entries for app_pwm.c and the corresponding library folder. On one test I copied the PWM Makefile and added the timer references to that. Same result. But without the timer references the ppm example builds OK. Something to do with PWM using timers I think.

RE: Timer and PWM (and BLE) in nRF5 v12

bjorn-spockeli — Mon, 31 Jul 2017 08:52:09 GMT

Hi Paul, the error undefined reference to app_pwm_init suggests that you have not added the app_pwm.c to the SRC_FILES in the makefile.

RE: Timer and PWM (and BLE) in nRF5 v12

paul_tanner — Mon, 31 Jul 2017 08:22:32 GMT

I might be able to figure this out myself if I understood the way the PPI stuff works. I see the PPI and GPIOTE examples but I don't understand them well enough. Is there any documentation?