D12320VF25IV Datasheet, PDF (822/1304 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 19 ROM
Do not set or clear the SWE bit during execution of a program 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,
flash memory can only be read in program-verify or erase-verify mode. Access flash memory only
for verify operations (verification during programming/erasing). Also, do not clear the SWE bit
during programming, erasing, or verifying.
Similarly, when using the RAM emulation function the SWE bit must be cleared before executing
a program or reading data in flash memory.
However, the RAM area overlapping flash memory space can be read and written to regardless of
whether the SWE bit is set or cleared.
Do not use interrupts while flash memory is being programmed or erased: When flash
memory is programmed or erased, all interrupt requests, including NMI, should be disabled 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 PROM 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.
Rev.6.00 Sep. 27, 2007 Page 790 of 1268
REJ09B0220-0600