Hi

Hopefully someone can help me with my issue.
We have self developed hardware with three ARM CPUs on the board.
For each one of the three CPUs we have connected a J-LINK PRO.

Now if I want to debug I always can only debug two of the three CPUs in parallel.
It is not possible to be able to debug all three in parallel and I cannot figure out why.

Interestingly the startup order of JLinkGDBServerCLExe does not matter. Its always the behaviour
that for the first two CPUs the startup works, the third one complains with:

Connecting to J-Link...
J-Link is connected.
Firmware: J-Trace PRO V2 Cortex-M compiled Feb 5 2021 14:50:19
Hardware: V2.00
S/N: 752001409
Feature(s): RDI, FlashBP, FlashDL, JFlash, GDB
Checking target voltage...
Target voltage: 2.98 V
Listening on TCP/IP port 4028
Connecting to target...
ERROR: STM32: Connecting to CPU via connect under reset failed.

ERROR: STM32: Connecting to CPU via connect under reset failed.

ERROR: Could not connect to target.

These are the startup commands we use for the three CPUs respectively:

./JLinkGDBServerCLExe -select IP=172.29.70.102 -port 4020 -swoport 5020 -telnetport 6020 -device STM32L151VE -endian little -if SWD -speed auto -noir -LocalhostOnly
./JLinkGDBServerCLExe -select IP=172.29.70.103 -port 4022 -swoport 5022 -telnetport 6022 -device nRF52840_xxAA -endian little -if SWD -speed auto -noir -LocalhostOnly
./JLinkGDBServerCLExe -select IP=172.29.70.104 -port 4028 -swoport 5028 -telnetport 6028 -device STM32F051C8 -endian little -if SWD -speed auto -noir -LocalhostOnly

Any ideas what I am doing wrong?

Regards

D. Hummel