TWI : No activity on SCL pin (27) when VDD is 1.8V

[SBharti]

Hi, 

I am using pin 27 as SCL and 26 as SDA on my custom board which is working on 1.8V. 

There is no activity on SCL pin, while i am getting correct values on SDA pin when seen on CRO.

At first i got doubt of connectivity of pins, so to test the connectivity on my board, i configured both pins as gpio and was doing PULLUP/PULLDOWN with 100millisecond delay and saw it is working. BUT it stopped working when i removed the delay, not even with 5millisec delay.

However, when i tested my firmware on "nrf52840DK" board, i saw correct waveform on both SDA/SCL lines.

Is it happening because my custom board is running on 1.8V?

Do i need to do some other configuration to use TWI at 1.8V / to use GPIO at high frequency at 1.8V?

                                                                

Running on nr552840DK board                                                                      Running on my custom board.

Regards

Suman

[Jared]

Hi,

This is regarding your custom board right? Not the development kit?

What frequency are you observing this at? Could you share a trace of it?

regards

Jared