How to enable P0.09 and P0.10 as GPIO pins on the nRF52 instead of NFC pins?

[singh]

Hi,

I'm using nrf52 custom board designed for our project,For this we have P0.09 and P0.10 as rx and tx used for uart, when i configured this two pins as rx and tx it is not showing any data on the uart.I have read the datasheet and i have seen this link devzone.nordicsemi.com/.../
but i'm not able to resolve the problem ,please help me ASAP.

Regards,

Prudhvi.

[bjorn-spockeli]

You simply need to define CONFIG_NFCT_PINS_AS_GPIOS in the preprocessor symbols in the ble_app examples that does not use the NFC antenna to use the pins as GPIOs.

It is also possible to write directly to the NFCPINS UICR register in order to use the pins as GPIO pins, i.e. add the following line to your code.

const uint32_t UICR_ADDR_0x20C    __attribute__((at(0x1000120C))) __attribute__((used)) = 0xFFFFFFFE

You will also need to follow some steps described in the comments below.

-Bjørn

[singh]

Thanks for reply ,

I have added in my code still the pins are not acting as gpio , is there any example code which i can take reference please help me regards, prudhvi

[bjorn-spockeli]

I do not know which SDK you are using, but in SDK v11.0.0 you can define CONFIG_NFCT_PINS_AS_GPIOS in the preprocessor symbols in the ble_app examples that does not use the NFC antenna to use the pins as GPIOs.

[manymany]

What will be the command for GCC because this one is not working?

    const uint32_t UICR_ADDR_0x20C    __attribute__((at(0x1000120C))) __attribute__((used)) = 0xFFFFFFFE
--> ../../../main.c:676:2: error: 'at' attribute directive ignored [-Werror=attributes]

[bjorn-spockeli]

I think you will have to define a section in the linker script, e.g. .uicrNfcPinsAddress, i.e.

 /** Location in UICR of NFC Pins register is stored. */ UICR_NFCPINS(r) : ORIGIN = 0x1000120C, LENGTH = 0x04 

SECTIONS { 
    /* Write the bootloader address in UICR. */ 
    .uicrNfcPinsAddress : 
    { 
         KEEP(*(.uicrNfcPinsAddress)) 
     } > UICR_NFCPINS
 } 

Then in the application code

const uint32_t UICR_ADDR_0x20C __attribute__ ((section(".uicrNfcPinsAddress"))) __attribute__((used));

[Eliot Stock]

@Bjorn You haven't assigned a value here. Did you mean to use 0xFFFFFFFE?