|Home > DAP components functional description > Memory Access Ports|
Memory Access Ports connect one memory system to another using one of the AMBA bus protocols AHB, APB, or AXI.
The Arm® Debug Interface Architecture Specification ADIv6.0 defines a Memory Access Port (MEM-AP) so that it provides two logical views of the access port to the debugger. These two views are referred to as twin APs or logical APs. In SoC-600, these two logical APs are contiguous in the memory map and each one of them occupies 4kB address space. An external debugger can only discover one of the twin APs through the ROM table. The other AP is dedicated for self-hosted debug. The MEM-AP itself is not capable of differentiating which of the twin APs is visible in the ROM table. The MEM_AP decodes the access requests on the APB slave interface and maps them to AP-L0 or AP-L1, based on the value of paddr_s.