App Timer tutorial, nrf_drv_clock_lfclk_request

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Anders Strand — Mon, 11 Apr 2016 07:33:12 GMT

I see your point :) This should be more visible. I will see if i can make some updates to developer.nordicsemi.com/

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Ladasky — Fri, 08 Apr 2016 19:57:41 GMT

Whoops. That could very well be the source of my problems, as well as a few other software bugs I haven't discussed in this thread. Thanks for the information. Somehow I only managed to see the message " we fixed a lot of bugs, so upgrade to the latest SDK," and not the message "except when you can't."

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Anders Strand — Fri, 08 Apr 2016 07:53:24 GMT

Hey. The PCA 10036 is not supported by the newest SDK and softdevices. You can see the compatibility matrix here. Your card has the Engineering A chip on it. Can you try with the supported SDK and Softdevice?

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Ladasky — Thu, 07 Apr 2016 19:55:31 GMT

Hello again Anders, thanks for staying with me. I am using the nRF52 Preview Kit, PCA10036. My development environment is pure Linux, using GCC with the ARM toolchain.

My code has every single line that the example you posted has, it's just organized a little differently. It still doesn't print the periodic message I want. I will try to copy your example and see what I get.

I am working on several other programs for the PCA10036. I've noticed that the Makefiles changed between SDK 9.1 and SDK 11. There are a lot more compiler flag settings in the most recent version. I'm not sure what they all do. Perhaps my CFLAGS in the Makefile require some changes. Where are all of the CFLAGS settings documented? There are so many.

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Anders Strand — Thu, 07 Apr 2016 12:08:04 GMT

Are you using the nRF52 Development kit, or a custom board? If DK, which version?

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Anders Strand — Thu, 07 Apr 2016 11:48:09 GMT

app_timer uses SWI0 to send timer interrupts to the application timer handler.

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Ladasky — Tue, 05 Apr 2016 19:41:47 GMT

Thanks for your reply, Anders. I thought that the purpose of the App Timer was to provide a higher-level interface than the RTC, and to make using multiple timers easy (I will eventually need two)? Does my App Timer code still need to reference the lower-level RTC functions?

In any case: the lfclk_config() in the SDK11 RTC example reads thus:

ret_code_t err_code = nrf_drv_clock_init();
APP_ERROR_CHECK(err_code);
nrf_drv_clock_lfclk_request(NULL);

My own code is nearly identical, the only difference is that I declare err_code on an earlier line. The App Timer tutorial shows nrf_drv_clock_lfclk_request being called with no arguments. Consistent with the SDK11 docs, that doesn't work for me. I get a compiler error because nrf_drv_clock_lfclk_request wants a pointer to a nrf_drv_clock_handler_item_t (NULL, or false, substitutes when you don't need a callback function).

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Anders Strand — Tue, 05 Apr 2016 14:53:21 GMT

Hey.

Documentation of the clock driver is found here.

The rtc example shows how to set up the rtc, as referenced by the APP_TIMER_INIT documentation:

This module assumes that the LFCLK is already running. If it is not, the module will be non-functional, since the RTC will not run. If you do not use a SoftDevice, you must start the LFCLK manually. See the rtc_example's lfclk_config() function for an example of how to do this. If you use a SoftDevice, the LFCLK is started on SoftDevice init.

Let me know if you need some code snippets

-Anders

UPDATE 7 April. Trying it out on PCA10040 (nRF52 DK)

I did the following, which let me print something periodically with a app_timer. It was compiled with Keil 5. I am not sure if this will help you or not, but at least we know that this works with the Keil compiler.

1: Start with the example project "uart" found in "nRF5_SDK_11\examples\peripheral".

2: include app_timer and clock headers. (and add the files to the include paths)

#include "app_timer.h"
#include "nrf_drv_clock.h"

3: define some timer variables

#define APP_TIMER_PRESCALER             0                                           /**< Value of the RTC1 PRESCALER register. */
#define APP_TIMER_OP_QUEUE_SIZE         4

4: Add the .c files to Keil (right click ->add existing files)

5: Create a timer id

APP_TIMER_DEF(periodic_print_id);

6: Create clock setup and timer handler

static void periodic_print(void * p_context){
    printf("\n Periodic print: \n\r");
}

static void lfclk_config(void)
{
    ret_code_t err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_clock_lfclk_request(NULL);
}

7: Edit main to initialize and start the timer task.

    lfclk_config();
    APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);
    err_code = app_timer_create(&periodic_print_id, APP_TIMER_MODE_REPEATED, periodic_print);
    APP_ERROR_CHECK(err_code);
    err_code = app_timer_start(periodic_print_id, APP_TIMER_TICKS(500, APP_TIMER_PRESCALER),NULL);
    APP_ERROR_CHECK(err_code);

RE: App Timer tutorial, nrf_drv_clock_lfclk_request

Ladasky — Mon, 04 Apr 2016 22:24:56 GMT

Following up to myself: I just discovered the function nrf_drv_clock_lfclk_is_running(). After executing this...

err_code = nrf_drv_clock_init();
APP_ERROR_CHECK(err_code);
nrf_drv_clock_lfclk_request(false);

...nrf_drv_clock_lfclk_is_running() returns FALSE. I have confirmed that I'm not starting LFCLK. From my reading, I think that nrf_drv_config.h and the Makefile may also affect the hardware. The App Timer tutorial says that App Timer uses RTC1. I have modified my nrf_drv_config.h to read:

#define RTC1_ENABLED 1

When RTC1 triggers, which software interrupt does it use? It might use SWI0, since the Makefile that comes with the App Time tutorial does not include the line:

CFLAGS += -DSWI_DISABLE0

I made sure that my Makefile also does not include this line. Any clues? Thanks again.