Disable NRF9160 I2C internal pull up. NRF91 with TXS0108

[Jupyter1336]

I finally got a working i2c code base but it seems that the nrf9160 has internal pullups on the i2C bus me trying to combine this with a TXS0108 causes weird issues. I suspect that the internal pull fights the internal pull up of the TXS0108 so I wanted to turn this off. How can I turn of these pullups in the 1.5.0 SDK

Image without the TXS01 show that is has internal pull-up

Image as soon as Output Enable is pulled high on TXS01

Its running the scanner example.

8561.i2c_scanner.zip

[Stian Røed Hafskjold]

Hi, sorry for the late reply. There is no way to do that through the zephyr driver API unfortunately, so you will have to change the nrfx TWIM drivers directly. More specifically:

In \modules\hal\nordic\nrfx\drivers\src\nrfx_twim.c,
in TWIM_PIN_INIT
change NRF_GPIO_PIN_PULLUP to NRF_GPIO_PIN_NOPULL

In \modules\hal\nordic\nrfx\drivers\src\nrfx_twi_twim.c,
in TWI_TWIM_PIN_CONFIGURE
change NRF_GPIO_PIN_PULLUP to NRF_GPIO_PIN_NOPULL

Best regards,
Stian