Does setting a pin to be TWI SCL or SDA enable its pullup?

[CurtisHx]

I have the nRF52 dev kit, and I hooked up pin 13 to SDA and pin 18 to SCL on an I2C device. There are no external pullups on the SDA or SCL lines.

However, the TWIM module appears to happily communicating with the slave. So does setting an IO to be a TWI line through the NRF_TWIM0->SCL/SDA registers automatically enable that IOs pullup? I couldn't find any information either way in the datasheet, and that seems like an important detail to know.

I'm bare-metal programming. No softdevice. No driver.

[Justin]

If you're using the driver it does enable the pull ups. See nrf_drv_twi.c line 44.

[milanez]

Hy, what your softdevice version ?

[CurtisHx]

@milanez No Softdevice. I've been bare-metal programming

[CurtisHx]

Forgot to note that I'm writing a driver for the I2C module and going directly after the hardware registers.

[Justin]

to be clear, are you setting NRF_GPIO->PIN_CNF ?