HD64F2149 Datasheet, PDF (733/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

The power-on and power-off timing requirements should also be satisfied in the event of a power
failure and subsequent recovery.
Use the recommended algorithm when programming and erasing flash memory: The
recommended algorithm enables programming and erasing to be carried out without subjecting the
device to voltage stress or sacrificing program data reliability. When setting the P or E bit in
FLMCR1, the watchdog timer should be set beforehand as a precaution against program runaway,
etc.
Do not set or clear the SWE bit during program execution in flash memory. Wait for at least
100 µs after clearing the SWE bit before executing a program or reading data in flash memory.
When the SWE bit is set, data in flash memory can be rewritten, but when SWE = 1 the flash
memory can only be read in program-verify or erase-verify mode. Flash memory should only be
accessed for verify operations (verification during programming/erasing). Do not clear the SWE
bit during a program, erase, or verify operation.
Do not use interrupts while flash memory is being programmed or erased: All interrupt
requests, including NMI, should be disabled when programming and erasing flash memory to give
priority to program/erase operations.
Do not perform additional programming. Erase the memory before reprogramming. In on-
board programming, perform only one programming operation on a 128-byte programming unit
block. In writer mode, too, perform only one programming operation on a 128-byte programming
unit block. Programming should be carried out with the entire programming unit block erased.
Before programming, check that the chip is correctly mounted in the PROM programmer.
Overcurrent damage to the device can result if the index marks on the PROM programmer socket,
socket adapter, and chip are not correctly aligned.
Do not touch the socket adapter or chip during programming. Touching either of these can
cause contact faults and write errors.
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