Motorola MPC533 Reference Manual page 998

Read/Write Access
22.5.2 Write Operation to Memory-Mapped Locations and
MPC500 Registers
22.5.2.1 Single Write Operation
For a single write access to memory-mapped locations and MPC500 registers, the
following sequence of operations need to be performed via the auxiliary port:
1. The tool confirms that the device is ready before transmitting download request
public message (TCODE=18).
2. The download request public message contains:
a) TCODE(18)
b) Access opcode 0xF which signals that subsequent data needs to be stored in the
RWA register.
c) Configure the RWA register fields as follows:
– Start/complete (1 to indicate start access) -> SC
– Read/write address (write address) -> RWAD
– Read/write (1 to indicate a write access) -> RW
– Word size (32 bits, 16 bits, 8 bits) -> SZ
– Write data (write data) -> WD
– Privilege (user data/instruction, supervisor data/instruction) -> PRV
– Map select (select memory map, 00 or 01) -> MAP
– Access Count (0 to indicate single access) -> CNT
3. After completion of the write operation, the device ready for upload/download
public message (TCODE=16) is transmitted to the tool indicating that the device is
ready for next access.
4. The SC bit is cleared to indicate that the write access is complete.
22.5.2.2 Block Write Operation
For a block write access to memory-mapped locations and MPC500 registers, the following
sequence of operations need to be performed via the auxiliary port:
1. The tool confirms that the device is ready before transmitting download request
public message (TCODE = 18).
2. The download request public message contains:
a) TCODE(18)
b) Access opcode 0xF which signals that subsequent data needs to be stored in the
RWA register.
c) Configure the RWA register fields as follows
22-66
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
MPC533 Reference Manual MOTOROLA