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22.7
Programming/Erasing Flash Memory
A software method, using the CPU, is employed to program and erase flash memory in the on-
board programming modes. There are four flash memory operating modes: program mode, erase
mode, program-verify mode, and erase-verify mode. Transitions to these modes are made by
setting the PSU1, ESU1, P1, E1, PV1, and EV1 bits in FLMCR1 for addresses H'000000 to
H'03FFFF.
The flash memory cannot be read while it is being written or erased. The flash memory cannot be
read while being programmed or erased. Therefore, the program (user program) that controls flash
memory programming/erasing should be located and executed in on-chip RAM or external
memory. If the program is to be located in external memory, the instruction for writing to flash
memory, and the following instruction, should be placed in on-chip RAM. Also ensure that the
DTC and DMAC is not activated before or after execution of the flash memory write instruction.
In the following operation descriptions, wait times after setting or clearing individual bits in
FLMCR1 are given as parameters; for details of the wait times, see section 25.6, Flash Memory
Characteristics.
Notes: 1. Operation is not guaranteed if bits SWE1, ESU1, PSU1, EV1, PV1, E1, and P1 of
FLMCR1 are set/reset by a program in flash memory in the corresponding address
areas.
2. When programming or erasing, set FWE to 1 (programming/erasing will not be
executed if FWE = 0).
3. Programming should be performed in the erased state. Do not perform additional
programming on previously programmed addresses.
805
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