Hardware Timer didnt work https://github.com/khoih-prog/ESP8266TimerInterrupt#why-using-isr-based-hardware-timer-interrupt-is-better
=> Software Timer https://ullisroboterseite.de/esp8266-timing.html#timer
#include <GDBStub.h>
...
void setup() {
Serial.begin(460800);
gdbstub_init();
GDB muss dafür compiled werden GDB-Version aus Arduino Toolchain hat Support
$ ./start_xtensa_gdb_stub.sh