PPK won't output over 2.2V on nRF52832 Preview DK

RE: PPK won't output over 2.2V on nRF52832 Preview DK

samsonc — Wed, 26 Jul 2017 22:20:00 GMT

See comments above. I misread the manual and it turns out that adjusting the output voltage with REG is not possible unless you are using an external J-link debugger, EVEN if the DUT is an external circuit and not the nRF5x DK.

RE: PPK won't output over 2.2V on nRF52832 Preview DK

samsonc — Wed, 26 Jul 2017 22:18:42 GMT

I realized that I misunderstood part of the manual. When using the PPK and nRF5x DK - even when the DUT is not the nRF5x DK, but an external device - the PPK and nRF5x DK MUST be the same voltage. I misunderstood the warning to mean only if the nRF5x DK is being used as the DUT. What happens is the debugger SWD lines for the J-link OB are unfortunately always at 3V, which reverse powers VDD and VDD_REG through the topside nRF5x, giving a minimum output voltage of about one diode drop below 3V, and very poor accuracy when the voltages are not matched.

RE: PPK won't output over 2.2V on nRF52832 Preview DK

samsonc — Wed, 26 Jul 2017 21:43:34 GMT

Wow - everything works now. Sounds like either something's wrong with my Preview DK or the Preview DK is somehow incompatible with the PPK. Recently got a normal DK, will check in a bit and then write up an update.

RE: PPK won't output over 2.2V on nRF52832 Preview DK

Hung Bui — Wed, 26 Jul 2017 14:14:47 GMT

@samsonc: Could you try again but without the DK connected ?

RE: PPK won't output over 2.2V on nRF52832 Preview DK

Chris — Fri, 21 Jul 2017 12:26:24 GMT

haha, 5 minutes ago I noticed the exact same :)