Charging indication by LED glow

[Rahul]

hello guys

i am trying to glow LED while my device gets charging. i have nrf52832  custom board and P0.17 connected to USB supply using voltage divider. when i plug in usb this pin 17 should be high and when i removed usb this pin sholud be low. but it is always high. what i am missing, can anyone suggest ? your help greatly appreciated.

i am doing like

#define BAT_CHG_STATE 17

if(BAT_CHG_STATE)
{
nrf_gpio_cfg_output(26);
nrf_gpio_pin_set(26);
}
else
{
nrf_gpio_pin_clear(26);
}

this functions are inside a loop and LED is glowing everytime when i am not charging the device.

thank you

[Martin]

Hi

waht you are trying to do is

you need to define pin 17 as input and detect the state with e.g. nrf_gpio_pin_read.

I would suggest to watch for the state change and not read, cfg and set in a loop.

I implemented it like this:

void init_power_detect(){
	nrf_drv_gpiote_in_config_t in_config = GPIOTE_CONFIG_IN_SENSE_TOGGLE(false);
	in_config.pull = NRF_GPIO_PIN_PULLUP;

	err_code = nrf_drv_gpiote_in_init(DEV_PIN_CHARGE, &in_config, pin_handler_charge);
	if(nrf_gpio_pin_read(DEV_PIN_CHARGE)){
		NRF_LOG_DEBUG("CHARGE ON > SENSE POWER OFF\r\n");
		nrf_gpio_cfg_sense_input(DEV_PIN_CHARGE, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
		nrf_gpio_pin_set(LED_CHARGE);
	} else {
		NRF_LOG_DEBUG("CHARGE OFF > SENSE POWER ON\r\n");
		nrf_gpio_cfg_sense_input(DEV_PIN_CHARGE, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_HIGH);
		nrf_gpio_pin_clear(LED_CHARGE);
	}
}

void pin_handler_charge(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action){
	if(pin == DEV_PIN_CHARGE)
	{
		switch(action){
		case NRF_GPIOTE_POLARITY_TOGGLE:
			if(nrf_gpio_pin_read(DEV_PIN_CHARGE)){
			    // 1 = Charging
				nrf_gpio_pin_set(LED_CHARGE);
			} else {
			    // 0 = NOT Charging
				nrf_gpio_pin_clear(LED_CHARGE);
			}
			break;
		}
	}
}

Cheers

[Rahul]

thanks for reply. i tried this when i plug in USB, LED is glowing but after removing USB , LED is ON only. 

[Martin]

Hi

try to set NRF_GPIO_PIN_PULLDOWN instead of UP.
I reworked my code to give an example, how to do it without loop, so there is no guaranty it works for you out of the box. ;-)

Cheers

[Rahul]

ok i will try sir

thank you

[Rahul]

yes, with pull down it is working fine thank you so much