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4. Do not apply a constant high level to the FWE pin
To prevent erroneous programming or erasing due to program runaway, etc., 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.
5. 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.
6. Do not set or clear the SWE bit during program execution in flash memory
Clear 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 flash memory should only be
accessed for verify operations (verification during programming/erasing).
7. Do not use interrupts while flash memory is being programmed or erased
All interrupt requests should be disabled during FWE application to give priority to
program/erase operations.
8. Do not perform additional programming. Erase the memory before reprogramming.
In on-board programming, perform only one programming operation on a 32-byte
programming unit block. In Writer mode, perform only one programming operation on a 128-
byte programming unit block. Programming should be carried out with the entire programming
unit block erased.
9. 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.
10. Do not touch the socket adapter or chip during programming.
Touching either of these can cause contact faults and write errors.
Rev.3.00 Jul. 19, 2007 page 165 of 532
6. ROM
REJ09B0397-0300
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