RTT message logging with power cycles

[rct42]

Greetings,

I've got an embedded project where a NRF52 is a "co-processor". The NRF52 used to output UART debug messages but I've since changed this to use RTT.

During operation, the main microcontroller frequently performs a power cycle on the NRF52. After the first NRF52 power cycle no further debug messages appear in the J-Link RTT Viewer (V6.18c, latest of 30/8/17). I can get the messages to reappear if I reopen the J-Link RTT Viewer but this is quite a hassle and I fear that I'm losing the debug information.

Has anyone else encountered this problem and found a solution to this?

Note:

1. The problem I am trying to debug is during the state changes / power cycles.
2. This may be a question for Segger, but will try here first.

[bjorn-spockeli]

Several other of my colleauges and I have also seen this issue, but we have not been able to find a solution either.

My suggestion would be to contact Segger regarding this issue.

[Turbo J]

How is the debugger's V_target connection wired up?

If it does not see the power drop of the NRF52, there is nothing the debugger can do - it will simply loose the debugging connection as the debug interface inside the NRF will be reset, too.

If it could see the power drop it may be possible to restart the debugging interface - but you will probably be much better of using a "high speed" UART(-2USB) connection.