Does nRF9160 have internal pull-up resistors for I2C(TWIM)?

[Yusuke]

When I read Objective Product Specification v0.7.1, it seems external pull-up resistors are required.

However, when I use TWIM without them, it works out.

Do I need external pull up resistors yet?

[Turbo J]

Look in the PS: Peripherials->GPIO->electrical specifications.

The pullup resistors are unusually small and thightly specified (compared to other MCUs I have flying around here). A pullup beween 11k and 16k is usable for I²C bus in many cases - but it will depend on bus load and -speed.

You want to check signal form with a scope.

[Yusuke]

Thanks!

Objective Product Specification v0.7.1, p100

Does MCU automatically set SCL and SDA pins as pull-up pins when I configure TWIM(I2C)?

[Turbo J]

Not the hardware directly, but the nrfx library does (TWIM_PIN_INIT macro).

[Yusuke]

Where is TWIM_PIN_INIT used? I couldn't find it in my ncs folder

[Turbo J]

It is in nrfx_twim.c from the SDK15.3 that I use here.

Not sure whether this ships the same way in nRF9160 compatible SDKs.