How to deal with a case when user takes a battery off while BLE communication?

RE: How to deal with a case when user takes a battery off while BLE communication?

Håkon Alseth — Mon, 22 Nov 2021 08:28:06 GMT

Hi,

[quote user="joojoo5"]

When it starts from power on button, the red light stayed about 2 seconds.

However, when it starts from NVIC_SystemReset(), then it stayed little about 2.5 more more seconds.

Can anyone explain why it happens like that?

[/quote]

When running on the internal HFCLK, you will see variations up to +/- 6%:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/clock.html?cp=4_2_0_18_3_0#unique_641326801

However, if you expect 2 seconds, but see 2.5 seconds in this specific loop:

[quote user="joojoo5"]nrf_gpio_pin_set(PIN25LED_RED);
nrf_delay_ms(2000);
nrf_gpio_pin_clear(PIN25LED_RED);[/quote]

that is quite strange. Do you measure pulse with a logic analyzer? If yes, can you share the results?

Please note that a startup from power-on-reset will take longer than a soft-reset, as the nRF will be kept in reset for a given time period to ensure that VDD is within a valid area:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/power.html?cp=4_2_0_17_9_1#unique_580976277

Kind regards,

Håkon

RE: How to deal with a case when user takes a battery off while BLE communication?

joojoo5 — Fri, 19 Nov 2021 00:11:35 GMT

After more careful investigation, I found that the above statements are not correct.

In fact, the bootloader is executed. However, the speed of execution is different.

See below code.

int main(void)
{
uint32_t ret_val;

(void) NRF_LOG_INIT(NULL);

NRF_LOG_INFO("Inside main\r\n");

nrf_gpio_cfg_output(PIN25LED_RED);

nrf_gpio_pin_set(PIN25LED_RED);
nrf_delay_ms(2000);
nrf_gpio_pin_clear(PIN25LED_RED);

buttons_init();

When it starts from power on button, the red light stayed about 2 seconds.

However, when it starts from NVIC_SystemReset(), then it stayed little about 2.5 more more seconds.

Can anyone explain why it happens like that?

PS: Please note that I had the delay time of 200ms before and I didn't see the red light. That was why I thought it didn't start from the bootloader. It came more apparent as I put more delay time. Please discard my original questions.

RE: How to deal with a case when user takes a battery off while BLE communication?

Håkon Alseth — Thu, 18 Nov 2021 12:39:58 GMT

It is not easy to state where it is stuck, especially without any logs.

When you power on the device, have you checked where it is stuck by attaching the debugger to a running target?

Kind regards,

Håkon

RE: How to deal with a case when user takes a battery off while BLE communication?

joojoo5 — Thu, 18 Nov 2021 11:51:41 GMT

Just want to correct myself.

Bootloader is not executed when power is on. But, when NVIC_SystemReset() is exucuted, the bootloader is executed.

Why is it working like that?

Is there a way I can do so that the bootloader is executed even when battery power is on?