nRF52840 debug out 1.8V MCU

[Chu]

Hi

I'm trying to use the nRF52840 DK debug out to program/flash an external nRF52840 IC that runs at 1.8V logic level. According to the manual, the DK is running at 3V via a buck converter.

Is it possible to change the feedback resistor pack and regulate the voltage down to 1.8V? If so, this would allow the DK to program the external MCU.

Alternatively, on the debug out header (P19), will 1.8V on pin-1 be enough to trigger EXT_VTG, i.e. the flasher recognises that an external MCU is connected? 

Thanks

Chu 

[Nguyen Hoan Hoang]

No, you need a level shifter to match the logic level.

[Chu]

Thanks! Could you recommend a level shifter in this case? I needs to have 4 bidirectional channels, and cope with 13K internal pull-up/down resistance.