Setting VEXT at a different level to VTG

RE: Setting VEXT at a different level to VTG

Hung Bui — Thu, 02 Jan 2014 10:04:31 GMT

It's correct, Eliot. You can find at section 8.23 in the nRF51822 Product Spec 2.0 that output high voltage for a GPIO pin is VDD-0.3V minimum.

RE: Setting VEXT at a different level to VTG

Eliot Stock — Mon, 30 Dec 2013 21:47:48 GMT

OK, thanks. I'll have to buy the J-Link and leave the whole device at 1.8V. Can you confirm though that it's not possible to run the UART pins at 1.8V while the nRF51822 itself is at 3.3V?

RE: Setting VEXT at a different level to VTG

Hung Bui — Mon, 30 Dec 2013 15:51:10 GMT

Hi Eliot,

For your issue, I think you should consider adding a level shifter for your UART pins. Another workaround is to use other debugger that support wider voltage range, such as this or this