SH7046 Datasheet, PDF (528/611 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7046 Series

Section 18 Flash Memory (F-ZTAT Version)
pin only when programming or erasing flash memory. Avoid creating a system configuration in
which a low level is constantly applied to the FWP pin. Also, while a low level is applied to the
FWP pin, the watchdog timer should be activated to prevent excess programming or excess
erasing 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 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 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. 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
while a low level is being input to the FWP pin, 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: All interrupt
requests, including NMI, should be disabled during FWP 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 EPROM programmer:
Overcurrent damage to the device can result if the index marks on the EPROM programmer
socket, socket adapter, and chip are not correctly aligned.
Do not touch the socket adapter or chip during programming: Casual contact with either of
these by hand or something while programming can generate a transient noise on the FWP and
RESET pins or cause incorrect programming or erasing due to bad electrical contact.
Reset the flash memory before turning on the power: If V_CC is applied to the RESET pin while
in high state, mode signals are not correctly downloaded, causing MCU's runaway. In a case
where FWP pin is in low state, incorrect programming or erasing can occur.
Rev. 4.00 Dec 05, 2005 page 484 of 564
REJ09B0270-0400