M37754FFCGP Datasheet, PDF (34/68 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER FLASH MEMORY VERSION

PRELIMINARY _{NSootimcee: pTahriasmisentroict} ^{alimfinitsalasrpeescuifbicjeactitotno. change.}
MITSUBISHI MICROCOMPUTERS
M37754FFCGP
M37754FFCHP
SHINGLE-CHIP 16-BIT CMOS MICROCOMPUTER FLASH MEMORY VERSION
Program command
When “4016" is written to the flash command register, the
M37754FFCGP and the M37754FFCHP enter the program mode.
Subsequently to this, if the instruction (for instance, STA or LDM in-
struction) for writing byte data in the address to be programmed is
executed, the control circuit of the flash memory executes the pro-
gram. The auto erase/erase/program busy flag of the flash memory
control register is set to “1" when the program starts, and becomes
“0" when the program is completed. Accordingly, after the write in-
struction is executed, CPU can recognize the completion of the pro-
gram by polling this bit.
The programmed area must be specified beforehand by the erase/
program area select bits.
During programming, watchdog timer stops with “FFF16” set.
Note: A programming operation is not completed by executing the
program command once. Always be sure to execute a pro-
gram verify command after executing the program command.
When the failure is found in this verification, the user must re-
peatedly execute the program command until the pass. Refer
to Figure 24 for the flow chart of the programming.
Program verify command
When “C016" is wr itten to the flash command register, the
M37754FFCGP and the M37754FFCHP enter the program verify
mode. Subsequently to this, if the instruction (for instance, LDA in-
struction) for reading byte data from the address to be verified (i.e.,
previously programmed address), the contents which has been writ-
ten to the address actually is read.
CPU compares this read data with data which has been written by
the previous program command. In consequence of the comparison,
if not agreeing, the operation of “program → program verify” must be
executed again.
Erase command
When writing “2016” twice continuously to the flash command regis-
ter, the flash memory control circuit performs erase to the area speci-
fied beforehand by the erase/program area select bits.
Auto erase/erase/program busy flag of the flash memory control reg-
ister becomes “1" when erase begins, and it becomes “0" when
erase completes. Accordingly, CPU can recognize the completion of
erase by polling this bit.
Data “0016” must be written to all areas to be erased by the program
and the program verify commands before the erase command is ex-
ecuted.
During programming, watchdog timer stops with “FFF16” set.
Note: The erasing operation is not completed by executing the erase
command once. Always be sure to execute an erase verify
command after executing the erase command. When the fail-
ure is found in this verification, the user must repeatedly ex-
ecute the erase command until the pass. Refer to Figure 24 for
the erasing flowchart.
Erase verify command
When “A016" is written to the flash command register, the
M37754FFCGP and the M37754FFCHP enter the erase verify
mode. Subsequently to this, if the instruction (for instance, LDA in-
struction) for reading byte data from the address to be verified, the
contents of the address is read.
CPU must erase and verify to all erased areas in a unit of address.
If the address of which data is not “FF16" (i.e., data is not erased) is
found, it is necessary to discontinue erasure verification there, and
execute the operation of “erase → erase verify” again.
Note: By executing the operation of “erase →erase verify” again
when the memory not erased is found. It is unnecessary to
write data “0016” before erasing in this case.
34