7.5.1 Enter the Debug Mode
To force the processor to enter the Debug state as soon as it comes out of Reset, a debugger sets DHCSR.C_DEBUGEN to 1 to enable halting debug and sets DEMCR.VC_CORERESET to 1 to enable vector catch on the Reset exception.
When the processor comes out of Reset, it sets DHCSR.C_HALT to 1 and enters the Debug state.
For more details, refer to the ARM v7-M Architecture Reference Manual - ARM DDI 0403E, Debug and Reset.
| Steps | Commands |
|---|---|
| Enable Debug | WriteD32(DHCSR, (DBGKEY | C_DEBUGEN)) |
| Enable Reset Vector Catch | WriteD32(DEMCR, VC_CORERESET) |
| Issue Halt | WriteD32(DHCSR, (DBGKEY | C_HALT)) |