nRF 52840DK PCA10056 versions: 1.0.0 versus 3.0.0 - Debug OUT

[dosamia]

Hi,

we have 10 nRF52840 DK's 8 are version 1.0.0 and 2 are version 3.0.0(purchased this week).

The older version 1.0.0(made in Norway) work perfect with our 3V boards we develop but new version 3.0.0(made in Poland) do not successfuly GND Detect our development boards. We program our boards via Debug OUT Connector P19.

On checking schematics of both boards we can see the following difference of Debug Out: (1.0.0 on left, 3.0.0 on right below)

 

Where has 'EXT GND DETECT" gone to? Has it been moved to another pin on P19?

Boards working in 1.0.0 do not work in 3.0.0

Any help gratefully appreciated.

Best regards,

Dosa

[Bendik Heiskel]

Hi Dosa,

The debugger chip was changed in v3.0.0, this changed the way external boards is detected. The earlier versions used voltage on EXT_VDD(pin 1) to detect external boards, but v3.0.0 uses ground on SWD0_SEL(pin 3) to detect the external board.

Your custom board must tie this pin to ground, or you can make a adapter cable that connects pin 3 and 5 together.

 

Best regards,

Bendik