Furthermore, it is a quite complex timing procedure to erase/program flash. Fortunately, the
MPC89x54A carried with convenient mechanism to help the user read/change the flash content.
Just filling the target address and data into several SFR, and triggering the built-in ISP
automation, the user can easily erase, read, and program the embedded flash and option
registers
OR1.
There are several SFR designed to help the user implement the ISP functionality.
SFR:
IFD
(ISP
Flash Data register):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
(Data to be written into flash, or data got from flash)
IFD is the data port register for ISP operation. The data in IFD will be written into the desired address in
operating ISP write and it is the data window of readout in operating ISP read.
SFR:
IFADRH
(ISP
Flash Address High):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
(High byte of the address pointing to flash memory)
IFADRH is the high-byte address port for all ISP modes.
SFR:
IFADRL
(ISP
Flash Address Low):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
(Low byte of the address pointing to flash memory)
IFADRL is the low-byte address port for all ISP modes.
SFR:
IFMT
(ISP
Flash Mode Table):
Bit-7
Bit-6
Bit-5
reserved
Bit-4
Bit-3
Bit-2
Bit-1
Mode Selection
Bit-0
Mode Selection
0
0
0
0
0
1
0
1
0
0
1
1
1
1
1
1
0
1
1
1
0
To Operate
Standby
AP-memory read
AP-memory/Data-flash program
AP-memory/Data-flash page erase
OR1 memory erase (IFADRL[0]=1).
OR1 memory read ( IFADRL[0] =1)
OR1 memory program ( IFADRL[0] = 1)
Note: OR0
cannot be changed by ISP operation. It can be accessed only by Writer. Only
OR1
can be
changed by ISP program.
28
MPC89x54A Data Sheet
MEGAWIN
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
