7.3.4.11 Reading and Writing Memory/SFR Registers
To read from or write to an internal resource, such as a memory or SFR registers,
the OCI Single Step mode is used. In this mode, the external debugger can feed in an
instruction sequence to perform the requested read/write operation. Read values are
placed into the accumulator, which may then be read out of the result register using the
DebugNOP
JTAG instruction.