Motorola MPC533 Reference Manual page 1000

Read/Write Access
22.5.3 Read Operation to Memory-Mapped Locations and
MPC500 Registers
22.5.3.1 Single Read Operation
For a single read 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 fields as follows:
– Start/complete (1 to indicate start access) -> SC
– Read/write address (read address) -> RWAD
– Read/write (0 to indicate a read access) -> RW
– Word size (32 bits, 16 bits, 8 bits) -> SZ
– Write data (0xXXXXXXXX-> WD [don't care])
– 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. Data read from the specified address is stored in the UDI register.
4. Once the read access is completed, the upload/download information public
message (TCODE = 19) is transmitted to the tool along with the data read from the
UDI register. This message also indicates that the device is ready for next access.
5. The SC field in the RWA register is cleared.
22.5.3.2 Block Read Operation
For a block read 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.
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PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
MPC533 Reference Manual MOTOROLA