I am using pin 8 (NFC pin) as SCL and pin 9 as SDA of nrf52832 on my custom board. Basically I have connected MPU9250 with these pins and I know that MPU9250 is NRFND, for testing I guess its OK to use. I have used 4.7k resistor for pull-up. For firmware part I am using nrfx library. When I use this library to configure other pins it works but not for these pins.
#include <zephyr/kernel.h> #include <stdio.h> #include "twi.h" #include "mpu9250.h" int main(void) { int err; err = twi_init(8U, 9U); if (err != 0) { printk("\rcould not initialize i2c\n"); } err = twi_enable(); if (err != 0) { printk("\rcould not enable i2c\n"); } uint8_t dummy[] = { 1, 2, 3, 4, 5 }; if (err == 0) { while (true) { err = twi_write(0xAA, 0xBB, dummy, sizeof(dummy)); if (err != 0) { printk("\rcould not enable i2c\n"); } } } printk("Hello World! %s\n", CONFIG_BOARD); return 0; }