I need to use pin 8 and pin 20 as outputs on the nRF52 DK, to be transferred to a custom board built with the nRF52810. I'm using SDK v15.x.x.
I need to drive PWM output through pin 20, and a simple digital HIGH/LOW from pin 8. I need to do so in a program that utilizes the SAADC and PWM peripherals, extended from the uart_example within the SDK (Nordic UART Service example). Upon using a scope I see that pins are not initialized to 0 volts while running the program. To debug, I erased all firmware from the nRF52 DK but still read 1.5V and 2.6V form pin 8 and 20 respectively.
Within my program, I've already added "CUSTOM_BOARD" and "CONFIG_NFCT_PINS_AS_GPIOS" to preprocessor definitions. I've also changed the UART RTS/CTS/RX/TX pin assignments to free up pins 8 and 20. When I scope on any other pins, for example 11 and 12 or 13 and 14, I see they are initialized to 0V and I can run my PWM functions correctly. When I change pin assignment to port 8 and 20, the pins have strange initial voltages and I need them to start at zero as well.
Here are my current preprocessor definitions:
BOARD_PCA10040
DEVELOP_IN_NRF52832
FLOAT_ABI_SOFT
INITIALIZE_USER_SECTIONS
NO_VTOR_CONFIG
NRF52810_XXAA
NRF52_PAN_74
NRF_SD_BLE_API_VERSION=6
S112
SOFTDEVICE_PRESENT
SWI_DISABLE0
DEBUG
CONFIG_NFCT_PINS_AS_GPIOS
CUSTOM_BOARD
I know that the PWM and GPIO work with other pins so the functions I have written are correct. I'm also using other GPIO pins on the board for other processes. I believe there must be some kind of hidden configuration somewhere I need to enable/disable to properly work with PO.08 and PO.20. Can anybody help me out?
