M37221 Mitsubishi, M37221 Datasheet - Page 49

• Manufacturer Part Number: M37221
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER
• Manufacturer: Mitsubishi

ROM CORRECTION FUNCTION
This can correct ROM data in ROM (64K bytes). Up to 2 addresses
(2 blocks) can be corrected, a program for correction is stored in the
ROM memory for correction. The ROM memory for correction is 32
bytes
Set an address of ROM data to be corrected into the ROM correction
address. When the value of the counter matches the ROM data ad-
dress in the ROM correction address, the main program branches to
the program for correction stored in the ROM memory for correction.
To return from the program for correction to the main program, the
op code and operand of the JMP instruction (total of 3 bytes) is needed
at the end of the program for correction. In the case that the blocks 1
and 2 are used in series, the above instruction is not needed at the
end of the block 1.
The ROM correction function is controlled by the ROM correction
enable register.
Notes 1 : Specify the first address (op code address) of each
2 : Use the JMP instruction (total of 3 bytes) to return from
3 : Do not set the same ROM correction address to the blocks
Block 1 : addresses 02C0
Block 2 : addresses 02E0
2 blocks.
instruction as ROM correction address.
the main program to the program for correction.
1 and 2.
16
16
to 02FF
to 02DF
16
16
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
M37221EF-XXXSP,M37221EFSP
Fig. 54. Structure of ROM correction enable register
Fig. 53. ROM correction addresses
7
ROM correction address 1 (high-order)
ROM correction address 1 (low-order)
ROM correction address 2 (high-order)
ROM correction address 2 (low-order)
with ON-SCREEN DISPLAY CONTROLLER
0
MITSUBISHI MICROCOMPUTERS
0
0
Fix these bits to “ 0.”
Block 1 enable bit
Block 2 enable bit
ROM correction enable register
(RCR : address 021B
0 : Disabled
1 : Enabled
0 : Disabled
1 : Enabled
0217
0218
0219
021A
16
16
16
16
)
16
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