5.3 Access Primitives
Based on MEM-AP access, the host (debugger PC utility) can rely on the following primitives:
Refer to ARM IHI 0031 for MEM-AP related sequence of transactions to read or write the memory.
| Memory Access Primitive | Description |
|---|---|
| Status ReadD8(U32 Addr, Value) | Read a byte (8 bits) from device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
| Status ReadD16(U32 Addr,Value) | Read half-word (16 bits) from device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
| Status ReadD32(U32 Addr,Value) | Read a word (32 bits) from device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
| Status WriteD8(U32 Addr,Value) | Write a byte (8 bits) to device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
| Status WriteD16(U32 Addr,Value) | Write half-word (16 bits) to device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
| Status WriteD32(U32 Addr,Value) | Write a word (32 bits) to device memory at address Addr Returns OK, FAULT, WAIT or ERROR |
Note: The user can use the speed-optimized primitives for block access using the auto-increment feature of the MEM-AP, but they are not mandatory to support all the device features. Refer ARM IHI 0031.
The rest of the document relies on this MEM-AP layer and the above-defined primitives to describe the interaction between the device and debugger.