I2C communication by NFC1/P0.09 as SCL and NFC2/P0.10 as SDA

[Sugiyama_DME_2]

I am using nRF52832.

Can I use NFC1/P0.09 as SCL and NFC2/P0.10 as SDA?

nRF52832_PS_v1.4.pdf states "The pin capacitance will be higher on these pins" in 4.3.2.

I am concerned if I2C communication does not work because NFC1/P0.09 and NFC2/P0.10 have high capacitance.

[Jørgen Holmefjord]

Hi,

According to the GPIO Electrical Specification, the capacitance on NFC pads are typical 4 pF vs 3 pF on normal pads:

I do not think this should have a big impact on the I2C bus. The I2C specifications say this:

"The external pull-up devices connected to the bus lines must be adapted to accommodate the shorter maximum permissible rise time for the Fast-mode I2C-bus. For bus loads up to 200 pF, the pull-up device for each bus line can be a resistor; for bus loads between 200 pF and 400 pF, the pull-up device can be a current source (3 mA max.) or a switched resistor circuit".

Best regards,
Jørgen

[Sugiyama_DME_2]

Hi, Jorgen,

Thank you for your reply.

I need to use NFC1/P0.09 as SCL and NFC2/P0.10 as SDA because other GPIO pins are assigned for other functions.

I will check I2C communication by using NFC1/P0.09 as SCL and NFC2/P0.10 as SDA with the evaluation board. 

Best regards,

Yasuyuki