H8SSLASH2218 datasheet(635/750 Pages) RENESAS

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Section 17 Flash Memory (F-ZTAT Version)

Rev.6.00 Jun. 03, 2008 Page 587 of 698

REJ09B0074-0600

17.13

Flash Memory Programming and Erasing Precautions

Precautions concerning the use of on-board programming mode, the RAM emulation function, and

PROM mode are summarized below.

• Use the specified voltages and timing for programming and erasing.

Applied voltages in excess of the rating can permanently damage the device. Use a PROM

programmer that supports the Renesas Technology microcomputer device type with on-chip

flash memory (FZTAT128V3A, FZTAT64V3A).

Do not select the HN27C4096 setting for the PROM programmer, and only use the specified

socket adapter. Failure to observe these points may result in damage to the device.

• Powering on and off

Do not apply a high level to the FWE pin until VCC has stabilized. Also, drive the FWE pin

low before turning off VCC. When applying or disconnecting VCC power, fix the FWE pin

low and place the flash memory in the hardware protection state. The power-on and power-off

timing requirements should also be satisfied in the event of a power failure and subsequent

recovery.

• FWE application/disconnection

FWE application should be carried out when MCU operation is in a stable condition. If MCU

operation is not stable, fix the FWE pin low and set the protection state. The following points

must be observed concerning FWE application and disconnection to prevent unintentional

programming or erasing of flash memory:

• Apply FWE when the VCC voltage has stabilized within its rated voltage range.

• In boot mode, apply and disconnect FWE during a reset.

• In user program mode, FWE can be switched between high and low level regardless of the

reset state. FWE input can also be switched during execution of a program in flash

memory.

• Do not apply FWE if program runaway has occurred.

• Disconnect FWE only when the SWE1, ESU1, PSU1, EV1, PV1, P1, and E1 bits in

FLMCR1 are cleared. Make sure that the SWE1, ESU1, PSU1, EV1, PV1, P1, and E1 bits

are not set by mistake when applying or disconnecting FWE.

• 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.

H8S/2218 Scheda tecnica(PDF) 635 Page - Renesas Technology Corp