External Pull ups I2C

[Edward_Atam]

Hello,

I'm using nrf52840 and i would like to ask if it possible to use the I2C bus without external pullups. I mean, i would like to avoid using external pullups

is there any configuration of the I2C bus in which the external pullpus can be avoided?

Thank you in advance.

[Dmitry]

Hi,

I2C will not work without pull-ups, as it's open-drain bus. You can configure internal pull-ups on SCL and SDA pins - they have 11-16k resistance according to spec, such configuration will work only in standard (100 kHz) mode and limited by ~75pF load capacitance.

[Edward_Atam]

Thanks,

How can I confgure the internal pull-ups?

[Dmitry]

If you're using TWI driver from SDK, it configures internal pull-ups by default. To configure manually, add these lines:

nrf_gpio_cfg(scl_pin, NRF_GPIO_PIN_DIR_INPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_S0D1, NRF_GPIO_PIN_NOSENSE);
nrf_gpio_cfg(sda_pin, NRF_GPIO_PIN_DIR_INPUT, NRF_GPIO_PIN_INPUT_CONNECT, NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_S0D1, NRF_GPIO_PIN_NOSENSE);

[Edward_Atam]

Thank you very much!