I2C on NFC lines

[Mark Samarin]

We have our SCL line on P0.10 (NFC2)  and SDA P0.23

When I try to start a I2C transaction nothing happens, and  NRF_TWIM0->TXD.AMOUNT = 0.  I have verified that SDA/SCL are pulled high.

However, I can run the same code changing the pins to P0.26, P0.27 as on the 52833-DK and I get an ERROR event with NRF_TWIM0->ERRSRC = 2, which is what you would expect with no devices on the bus.

I then tried the experiment on the 52833-DK, setting up GPIO pullups on SDA/SCL and got exactly the same results based on pin numbers.

We do not use NFC, and I have verified that the NFC module is not enabled in an emulator.   Is there a restriction on using the NFC lines for I2C?

Thanks,

Mark

[Simonr]

Hi Mark

You'll have to specifically configure the NFC pins as such if you want to use them as GPIOs. You can configure these pins as GPIOs by defining the CONFIG_NFCT_PINS_AS_GPIOS variable in your project settings. Please do so and try again.

Best regards,

Simon

[Mark Samarin]

Thanks that did it :-)