Portenta H7 M4 core stops after one loop

Official Hardware Portenta Family Portenta H7
1

Hi there,
I want to send variables from the M4 core to the M7 core via the RPC.
My problem is, that the M4 core stops after one loop,
so 41000 is received in the M7, and the blue led stays blue..
Also the compiler gives one warning:

/Users//Library/Arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld:/private/var/folders/f6/pwrqhmvx22s9qt6c96xsmg940000gn/T/arduino-sketch-D641DE4086A9B4D852C2E0B2296E2BEA/linker_script.ld:102: warning: memory region `DTCMRAM' not declared

#include "RPC.h"
void setup(){
  RPC.begin();
  pinMode(LEDB, OUTPUT);
}

int32_t send= 40000;
bool toggle;
void loop(){
  send <160000 ? send=send+1000 : send=1000;
  RPC.call("setRPCvar", send);
  delay(1000);
  toggle = !toggle;
  toggle ? digitalWrite(LEDB, HIGH) : digitalWrite(LEDB, LOW);
}

anyone an idea? what could be wrong here?

Thanks :slight_smile:

2

I would take this "warning" as 'DTCMRAM not declared' very serious:
If some code seems to use DTCMRAM, e.g. for a shared variable, the RPC ... it is only accessable by CM7, not by CM4.
The CM4 would hang if it would try to read from a non-existing memory address (and CM7 DTCM is not available for CM4).

So, fix this "warning" (which sounds very serious to me) first.
If the linker remaps variables, e.g. used as shared memory between CM7 and CM4, but the code will assume those at a dedicated address - all is broken (communication between both cores 'disconnected').

It looks to me: you have a problem with your linker script.