I need the NRF58240 chip on my NRF52840 DK to operate at 1.8V (because I have some 1.8V only peripherals to connect to it) while I'm still debugging the NRF58240 using the interface MCU on-board the NRF52840 DK.
The ticket here:
https://devzone.nordicsemi.com/f/nordic-q-a/22869/nrf52840-pdk-debugging-with-1-8v-periphery
...suggests that I can do this by flipping the VExt->nRF switch to ON and supplying 1.8V to the External Supply pins. I have done this but I find that my debug connection into the USB port J2 no longer works. Have I misunderstood the configuration instructions? I tried to follow the link in the ticket but it no longer works.
There is a note in the NRF52840 DK manual, section 8.3.5, saying "it is recommended to supply the VDD domain from a different source to prevent the pins of the SoC to be connected to unpowered devices": could that be my problem? If so, how do I go about "supplying the VDD domain from a different source"? Do I just supply 5V to one of the board pins, if so which one?
Thanks in advance for your help with this.
Rob
