RE: GPIO voltage output

MartinBL — Thu, 09 Jun 2016 12:18:31 GMT

To simply configure a GPIO pin as an output and set it high or low you can e.g. do this:

// Configure pin 5 as output
nrf_gpio_cfg_output(5);
// Set pin 5 high
nrf_gpio_pin_set(5);
// Set pin 5 low
nrf_gpio_pin_clear(5);

If you set the pin high its voltage will be VDD, if you set it low the voltage will be 0. You can configure each GPIO pin in high drive or standard drive. In standard drive you can source/sink 0.5mA. In high drive the pin can source/sink 5mA. You can source/sink a total of 15mA. So for example 3 x 5 mA, 5 x 3 mA, etc.

It is absolutely not recommended to use the LDO to power anything external. The LDOs are used to power internal circuits such as the radio, the CPU, and the flash. If you use them to power anything else you might induce voltage ripples, surges, etc. that can affect the circuits. The reason why the LDO's output voltage is even routed to a pin is so that you can add an external decoupling capacitor. If you connect anything to the LDOs you do so at your own discretion.

RE: GPIO voltage output

wlgrd — Thu, 09 Jun 2016 08:38:34 GMT

I think the data sheet says maximum current draw for the gpiote module is 15mA. Wouldn't recommend to power anything external with that. You could drive a transistor instead for such things.