does nRF51 has optional internal pullup resistors on some pins?

[makouda]

I'm working with nrf51 board, I'm using I2C to communicate with an accelerometer (see the scheme), the communications are successful but I dont see any pull up resistors in the lines SDA and SCL.

could I2C work without pull-up resistors or is the scheme wrong or does the accelerometer has internal pull up on lines SDA and SCL

this answer is saying that the pull-ups are probably in the microcontroller, is this right?

check better scheme on attachementSCH B115C2_AL_VC1_38L_DSN_20150804.pdf

as

[Johannes Lorenz]

Hi, in the SDK 9.x in the section GPIO abstraction you will find some information about enabling/disabling the internal pullup resistors:

enum nrf_gpio_pin_pull_t
// Enumerator used for selecting the pin to be pulled down or up at the time of pin configuration.

NRF_GPIO_PIN_NOPULL -> Pin pullup resistor disabled.
NRF_GPIO_PIN_PULLDOWN -> Pin pulldown resistor enabled.
NRF_GPIO_PIN_PULLUP -> Pin pullup resistor enabled.

A Ohm-value about the internal resistors, I could not find.

HTH Johannes