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Do not apply a constant high level to the FWE pin
Apply a high level to the FWE pin only when programming or erasing flash memory. A system
configuration in which a high level is constantly applied to the FWE pin should be avoided. Also,
while a high level is applied to the FWE pin, the watchdog timer should be activated to prevent
overprogramming or overerasing due to program runaway, etc.
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 P1
or E1 bit in FLMCR1, the watchdog timer should be set beforehand as a precaution against
program runaway, etc.
Do not set or clear the SWE1 bit during execution of a program in flash memory
Wait for at least 100 s after clearing the SWE1 bit before executing a program or reading data in
flash memory. When the SWE1 bit is set, data in flash memory can be rewritten, but access flash
memory only for verify operations (verification during programming/erasing). Also, do not clear
the SWE1 bit during programming, erasing, or verifying.
Similarly, when using emulation by RAM with a high level applied to the FWE pin, the SWE1 bit
should be cleared before executing a program or reading data in flash memory. However,
read/write accesses can be performed in the RAM area overlapping the flash memory space
regardless of whether the SWE1 bit is set or cleared.
Do not use interrupts while flash memory is being programmed or erased
All interrupt requests, including NMI, should be disabled during FWE1 application 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 programmer 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.