Using AIN pin as GPIO on nRF52820

RE: Using AIN pin as GPIO on nRF52820

Susheel Nuguru — Mon, 31 Oct 2022 08:24:53 GMT

[quote user="janvb"]I now understand that the problem is that the LED threshold voltage is smaller than VDDH-VDD, so that current is flowing through the LED into the pin when high. What is the best way to resolve this? [/quote]

You should probably fix this first so that extra current does not flow back to the pin

RE: Using AIN pin as GPIO on nRF52820

janvb — Thu, 27 Oct 2022 12:09:41 GMT

VDD is 1.8V, the battery powering the system is at 3.8V and connected to the VDDH pin. As the anodes of the LEDs are also connected to VDDH, I now understand that the problem is that the LED threshold voltage is smaller than VDDH-VDD, so that current is flowing through the LED into the pin when high. What is the best way to resolve this?

Can I use an open drain output? But in that case the pin voltage will rise above VDD when the pin is high, so that is violating the max ratings.

RE: Using AIN pin as GPIO on nRF52820

Susheel Nuguru — Thu, 27 Oct 2022 11:38:04 GMT

[quote user=""]This does not work in the software, when I drive the pin high with nrf_gpio_pin_set, the pin goes to 2V instead of VDD.[/quote]

What is the value of VDD you are using? Assuming that this is a custom board, it is hard to say what is limiting the output voltage. Also are you using high drive setting ? Did you get your schematics and layout files reviewed? Are you sure there is nothing in the hardware design or build that might cause the issues?