Serial1 problem (nRF52840)

[djdehaan]

Hi all, I have serious trouble getting Serial1 to work.
I am using nRF52840 (XXAA) board with NimBLE and thus n-able. In platformio. I am able to have Serial to work on pins defined by me, by setting (i #defined the ports to the right ids):
Serial.setPins(P1_13, P0_28);
Serial.begin(115200);

I try to do the same with Serial1, but it will crash on Serial.begin(115200).
I tried to declare Serial1, but cannot figure out how. And I found out that adding some config parameters to platform.ini may be relevant, but it still crashes on Serial.begin(115200). My platform.ini looks like this:

[env:Nim-nrf52840server]
platform = https://github.com/h2zero/platform-n-able.git@^1.0.0
board = nrf52840_dj
framework = arduino
monitor_speed = 115200
upload_protocol = jlink
lib_deps =
h2zero/NimBLE-Arduino@^2.1.0
milesburton/DallasTemperature@^3.11.0
upload_port = COM9
extra_scripts =
pre:build_versioning.py
board_bootloader = adafruit
build_flags =
${env.build_flags}
-DNRF52_SERIES
-DNRF52840_XXAA
-DCONFIG_NIMBLE_CPP_LOG_LEVEL=5
-DCORE_DEBUG_LEVEL=5

Can anyone help me with that Serial1 problem, how do I make that work, or what flags do I need to add?
Many thank for any help, DJ

[djdehaan]

Ok, I solved the problem with the help of h2zero. I am using a E73-2G4M08S1C module witch is not listed as board. I have my own PCB for my application. So I create my own board-definition, and I just found out 2 things that may be handy for other people new to n-able using platformio:

you must write the bootloader to the nRF first yourself ( I am using the nRF connect programmer for that). I was under the impression that it would all be uploaded together, but that is not valid for the bootloader. Burn it yourself.
i derived the board definition first from the nRF52840_DK, but that enables not the USB function in the nRF. I now derived a board definition from the Adafruit Feather Sense, and then it all works! So I can use Serial for debugging, and Serial1 for connecting to my sensor.