RE: ble_app_hrs_freertos example questions

Susheel Nuguru — Wed, 11 Dec 2019 12:14:07 GMT

we can continue the discussion in the other thread.

RE: ble_app_hrs_freertos example questions

samsam — Tue, 10 Dec 2019 15:19:27 GMT

As this thread was not accepting any Replies until now, I already posted a new Question

https://devzone.nordicsemi.com/f/nordic-q-a/55460/ble_app_hrs_freertos-2

which is actually a continuation of this thread. If there is moderator - feel free to merge both if you find it appropriate. Thanks

RE: ble_app_hrs_freertos example questions

Susheel Nuguru — Tue, 10 Dec 2019 12:18:02 GMT

First of all, the FreeRTOS is not running on app_timer.c but instead running on app_timer_freertos.c.

Which means that its timings are not dictated by sdk_config.h but instead the define in FreeRTOSConfig.h -> configTICK_RATE_HZ

You are not totally wrong though.

We cannot get the granualarity of 1ms exactly using a 32768 Hz timer. Since configTICK_RATE_HZ = 1024Hz, one tick is equal 1/1024 seconds, which = 0.976ms.

For realtime systems that need that can of granularity you should use portTICK_PERIOD_MS(time_in_ms) as below

#define FIRST_CONN_PARAMS_UPDATE_DELAY      portTICK_PERIOD_MS (5000)           /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */

#define NEXT_CONN_PARAMS_UPDATE_DELAY       portTICK_PERIOD_MS (30000)          /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */

Even though this is a bit harmless in current conditions, I can see that it could lead to bad results if the user has changed the configTICK_RATE_HZ rate to cause any other tick different than almost 1ms.

Thanks for lettings us know this.

[quote user=""]%s specificator for nrf_log_* doesn’t work in ble_app_hrs_freertos[/quote]

instead of uint8_t define bc_buf2 as char. String literals work with char and not uints

[quote user=""] In sdk_config.h APP_TIMER_CONFIG_RTC_FREQUENCY 1 (template ) vs 0 (hrs_freertos) - what is the objectives to use once 0 (32768 Hz) vs 1 (16384 Hz) ?[/quote]

This define should be irrelevant in your use case since with freeRTOS you are not using app_timer.c file where the above mentioned define becomes valid.

Since you should only use app_timer_freertos.c, the value above is not used