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82
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
M37274MA-XXXSP
PRELIMINARY
Notice:
This
is not
a final
specification.
Some
paramentic
limits
are
subject
to change.
MITSUBISHI MICROCOMPUTERS
Fig. 92. ROM Correction Enable Register
Fig. 91. ROM Correction Address Registers
ROM CORRECTION FUNCTION
This can correct program data in ROM. Up to 2 addresses (2 blocks)
can be corrected, a program for correction is stored in the ROM cor-
rection memory in RAM. The ROM memory for correction is 32 bytes
! 2 blocks.
Block 1 : addresses 02C016 to 02DF16
Block 2 : addresses 02E016 to 02FF16
Set the address of the ROM data to be corrected into the ROM cor-
rection address register. When the value of the counter matches the
ROM data address in the ROM correction address, the main pro-
gram branches to the correction program stored in the ROM memory
for correction. To return from the correction program to the main pro-
gram, the op code and operand of the JMP instruction (total of 3
bytes) are necessary at the end of the correction program. When 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
instruction as the ROM correction address.
2 : Use the JMP instruction (total of 3 bytes) to return from
the main program to the correction program.
3 : Do not set the same ROM correction address to blocks
1 and 2.
024216
ROM correction address 1 (high-order)
024316
ROM correction address 1 (low-order)
024416
ROM correction address 2 (high-order)
024516
ROM correction address 2 (low-order)
0
7
Fix these bits to “ 0.”
ROM correction enable register
(RCR : address 024616)
0
0 : Disabled
1 : Enabled
0 : Disabled
1 : Enabled
Block 1 enable bit
Block 2 enable bit