NRF52832 As to the usage of timer in Advertising mode

RE: NRF52832 As to the usage of timer in Advertising mode

Edvin — Tue, 26 Jun 2018 06:56:44 GMT

Hello,

That is great news. Timer 3 and Timer 2 has a different amount of CC registers, as you can see here, which may cause some issues when changing timers.

I don't know what implementation you went with, but I have also seen that there are some differences in the default configuration for the different timers,

Anyway, it's good that it is working now.

Best regards,

Edvin

RE: NRF52832 As to the usage of timer in Advertising mode

edmond.yun — Mon, 25 Jun 2018 23:37:19 GMT

Hello, Edvin,

I don't give up following your opinion and trying to implement it with the example,

and then finally I succeeded to make the waveform and when doing test with BLE communication,

the waveform is not shaking any more, thankful for your kindness and tireless determination,

I got some mistakes to define the timer, I tried to change the timer from 3 to 2....

after using the example as it is, I didn't have any problem,...

thanks.

RE: NRF52832 As to the usage of timer in Advertising mode

Edvin — Mon, 25 Jun 2018 09:12:40 GMT

Hello,

What IDE do you use?

Can you see why it resets? Try to define DEBUG in your preprocessor defines, and disable optimization (set it to -O0). Then see if the error handler catches why it is resetting.

Did you get the waveform that you desire in your original project before starting the advertising? You will need some extra components to be able to get negative voltage.

If you want me to look at your project, please send a zipped project folder.

BR,

Edvin

RE: NRF52832 As to the usage of timer in Advertising mode

edmond.yun — Mon, 25 Jun 2018 03:34:41 GMT

Hello, Edvin,

I tried to make the example by using the example of gpiote of SDK 14.0.1 ....as follows,

but the waveform is not perfect for my case, I need your help,

if possible, Could you please kindly help to implement the following waveform with my code ?

thankful for your kindness in advance,

thanks....

#define TCS_ON1 24//love_1116 BSP_LED_2
#define TCS_ON2 25//love_1116 BSP_LED_2

static nrf_drv_timer_t timer = NRF_DRV_TIMER_INSTANCE(2);

void timer_dummy_handler(nrf_timer_event_t event_type, void * p_context){}

static void led_blinking_setup()
{
uint32_t compare_evt_addr, compare_evt_addr_1, compare_evt_addr_2, compare_evt_addr_3;
uint32_t gpiote_task_addr, gpiote_task_addr_1, gpiote_task_addr_2, gpiote_task_addr_3;
nrf_ppi_channel_t ppi_channel, ppi_channel_1, ppi_channel_2, ppi_channel_3;
ret_code_t err_code;
nrf_drv_gpiote_out_config_t config = GPIOTE_CONFIG_OUT_TASK_TOGGLE(false);

err_code = nrf_drv_gpiote_out_init(TCS_ON1, &config);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_gpiote_out_init(TCS_ON2, &config);
APP_ERROR_CHECK(err_code);

//love_0625 250-5-250, 60hz based on 500 resistance.
nrf_drv_timer_extended_compare(&timer, (nrf_timer_cc_channel_t)0, nrf_drv_timer_us_to_ticks(&timer, 250), NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, false);//1 us,
nrf_drv_timer_extended_compare(&timer, (nrf_timer_cc_channel_t)1, nrf_drv_timer_us_to_ticks(&timer, 255), NRF_TIMER_SHORT_COMPARE1_CLEAR_MASK, false);//1 us,
nrf_drv_timer_extended_compare(&timer, (nrf_timer_cc_channel_t)2, nrf_drv_timer_us_to_ticks(&timer, 505), NRF_TIMER_SHORT_COMPARE2_CLEAR_MASK, false);//1 us,
nrf_drv_timer_extended_compare(&timer, (nrf_timer_cc_channel_t)3, nrf_drv_timer_us_to_ticks(&timer, 16665), NRF_TIMER_SHORT_COMPARE3_CLEAR_MASK, false);//1 us,

err_code = nrf_drv_ppi_channel_alloc(&ppi_channel);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_alloc(&ppi_channel_1);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_alloc(&ppi_channel_2);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_alloc(&ppi_channel_3);
APP_ERROR_CHECK(err_code);

compare_evt_addr = nrf_drv_timer_event_address_get(&timer, NRF_TIMER_EVENT_COMPARE0);
gpiote_task_addr = nrf_drv_gpiote_out_task_addr_get(TCS_ON1);

compare_evt_addr_1 = nrf_drv_timer_event_address_get(&timer, NRF_TIMER_EVENT_COMPARE1);
gpiote_task_addr_1 = nrf_drv_gpiote_out_task_addr_get(TCS_ON1);

compare_evt_addr_2 = nrf_drv_timer_event_address_get(&timer, NRF_TIMER_EVENT_COMPARE2);
gpiote_task_addr_2 = nrf_drv_gpiote_out_task_addr_get(TCS_ON2);

compare_evt_addr_3 = nrf_drv_timer_event_address_get(&timer, NRF_TIMER_EVENT_COMPARE3);
gpiote_task_addr_3 = nrf_drv_gpiote_out_task_addr_get(TCS_ON2);

err_code = nrf_drv_ppi_channel_assign(ppi_channel, compare_evt_addr, gpiote_task_addr);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_assign(ppi_channel_1, compare_evt_addr_1, gpiote_task_addr_1);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_assign(ppi_channel_2, compare_evt_addr_2, gpiote_task_addr_2);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_assign(ppi_channel_3, compare_evt_addr_3, gpiote_task_addr_3);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_enable(ppi_channel);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_enable(ppi_channel_1);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_enable(ppi_channel_2);
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_ppi_channel_enable(ppi_channel_3);
APP_ERROR_CHECK(err_code);

nrf_drv_gpiote_out_task_enable(TCS_ON1);
nrf_drv_gpiote_out_task_enable(TCS_ON2);
}

void Hal_Tcs_PPI_Timer_Start(void)//love_0625
{
ret_code_t err_code;

err_code = nrf_drv_ppi_init();
APP_ERROR_CHECK(err_code);

err_code = nrf_drv_gpiote_init();
APP_ERROR_CHECK(err_code);

nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
err_code = nrf_drv_timer_init(&timer, &timer_cfg, timer_dummy_handler);
APP_ERROR_CHECK(err_code);

// Setup PPI channel with event from TIMER compare and task GPIOTE pin toggle.
led_blinking_setup();

// Enable timer
nrf_drv_timer_enable(&timer);
}

RE: NRF52832 As to the usage of timer in Advertising mode

edmond.yun — Mon, 25 Jun 2018 00:57:12 GMT

Hello, Edvin,

Today I tested the code that you updated, but the result is not good,, compile is ok, but it can't be normally operated,

system has reset status repeatedly, ....

I think that I need to use the following example, because I am using the latest SDK(14.1.0) for nrf52832,

if right, please help to provide the example by referring the code that I update...

https://github.com/bjornspockeli/nRF52_ppi_timper_gpiote_example/blob/master/main.c

thanks.

RE: NRF52832 As to the usage of timer in Advertising mode

edmond.yun — Sun, 24 Jun 2018 07:44:01 GMT

Hello Edvin,

Thankful for your information firstly, I have a question as to your proposal,

I wonder whether your proposal can implement the following case, please help to check the case,

thanks.

concern is the period, 125 next 5 next 250 with 2 gpio pins,

125us (micro second)

|---------| |-------------| ==> repeat the same waveform.....

| | |

| |____ ____________________________________| => 0 volatge...

5us | |

| |

|_______|

250 us

|-------------------------------------------------------------------------------------------|

60 Hz or 10Khz.....

RE: NRF52832 As to the usage of timer in Advertising mode

Edvin — Fri, 22 Jun 2018 12:58:34 GMT

Hello,

This looks like a classic textbook example of a situation where a PPI would be suitable.

This is because you have a timer with a timeout that is quite fast, meaning that the timeout handler is called very frequently (it looks like it is set to 5µs.

While this may just work without the softdevice, but when you start using the softdevice (starting the advertisements), then the softdevice will take over the CPU at the advertising events, which means that you will not get the interrupts when the softdevice is doing it's advertising operations.

If you set up the PPI with a timer this can run in the background, not using the CPU. This means that it will be executed even though the softdevice is doing advertisement operations.

See the attached main.c file. This sets up the PPI with TIMER3, and controls the two LEDs LED_1 and LED_2 on the DK.

devzone.nordicsemi.com/.../main.c

If you only intend to toggle pins, this is the way to go. If you intend to do bigger operations then you need a different approach.

The main.c file was written in SDK14.0.0, but it is fairly simple, so it should run on any SDK with the nRF52832.

If you want to change the time the LEDs/pins should be high during runtime, you can use the function that is commented out, gpio_set_ticks(). Just modify it to set the correct register.

Best regards,
Edvin