
CPU Rewrite Mode
Specifications in this manual are tentative and subject to change
Rev. E
MITSUBISHI MICROCOMPUTERS
M30245 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
190
Microcomputer Mode and Boot Mode
The control program for CPU rewrite mode must be written into the user ROM or boot ROM area in
parallel I/O mode. If the control program is written into the boot ROM area, the standard serial I/O
mode becomes unusable.
Normal microcomputer mode is entered when the microcomputer is reset when pulling CNVSS pin
low. In this case, the CPU starts operating using the control program in the user ROM area.
When the microcomputer is reset by pulling the P55 pin low, and the CNVSS pin and P50 pin high,
the CPU starts operating using the control program in the boot ROM area. This mode is called the
“boot” mode. The control program in the boot ROM area can also be used to rewrite the user ROM
area.
Block Address
Block addresses refer to the maximum even address of each block. These addresses are used in
the block erase command, lock bit program command, and read lock status command.
Software Commands
Table 1.67 lists the software commands available with the M30245 (flash memory version).
After setting the CPU rewrite mode select bit to 1, write a software command to specify an erase
or program operation. When entering a software command, the upper byte (D8 to D15) is ignored.
Table 1.67.
List of software commands
Note 1: When a software command is input, the data high-order byte (D8 to D15) is ignored.
Note 2: SRD= Status register data
Note 3: WA = Write address, WD = Write data.
WA and WD must be set sequentially from 0016 to FE16 (even byte address). The page size is 256 bytes.
Note 4: BA = Block address. Enter the maximum address of each block that is an even address.
Note 5: D6 corresponds to the block lock status. When D6 = "1", the unlocked blocks are "0".
Note 6: X denotes a given even address in the user ROM area.
Command
First bus cycle
Second bus cycle
Third bus cycle
Mode
Address
Data
(D0 to D7)
Mode
Address
Data
(D0 to D7)
Mode
Address
Data
(D0 to D7)
1
Read array
Write
X (Note 6)
FF16
2
Read status register
Write
X
7016
Read
X
SRD (Note 2)
3
Clear status register
Write
X
5016
4
Page program (Note 3)
Write
X
4116
Write
WA0 (Note 3)
WD0 (Note 3)
Write
WA1
WD1
5
Block erase
Write
X
2016
Write
BA (Note 4)
D016
6
Erase all unlocked blocks
Write
X
A716
Write
X
D016
7
Lock bit program
Write
X
7716
Write
BA
D016
8
Read lock bit status
Write
X
7116
Read
BA
D6 (Note 5)