Assigning a functional block to a GPIO

Question

I'm confused about how to assign a functional block's I/O (TWI in my case) to a particular pin on the device. Is there a worked and documented example? Is there a relevant application note?

Håkon Alseth · Accepted Answer

Hi, 
 Take a look at this example in the SDK:
C:\Nordic Semiconductor
RF51 SDK_v4.3.0.27417\Nordic
rf51822\Board
rf6310	wi_sw_master_example 
 The pin definition is shown in file "twi_master_config.h".
This example uses a bit banged TWI, but if you switch that file with "twi_hw_master.c" instead, then you use the HW peripheral instead. 
 The pin selection is done on these two lines:
NRF_TWI1->PSELSCL = TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER;
NRF_TWI1->PSELSDA = TWI_MASTER_CONFIG_DATA_PIN_NUMBER; 
 The defines are basically a GPIO number (between 0 - 30).
These two GPIOs will then be controlled by the TWI HW module until you disable the TWI.