Im learning the debug progress to access memory system in a mcu
now i know how to read/write a register with a specific address
:write TAR and DRW in the AHB-AP
but how does AHB-AP read/write a core register like pc or sp which have no address
This was the first AP type to be introduced and was first used on Cortex-M based MCUs. The AHB-AP acts like a second memory interface to the system memory and debug registers of the CPU core. In this setup, the AHB-AP and the CPU core share the same 4 GB address space. This means, the debug registers are accessible via the debug interface as well as from the CPU core itself. official site