H8SSLASH2224 datasheet(831/1071 Pages) RENESAS

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Section 20 Flash Memory (F-ZTAT Version)

Rev. 5.00 Aug 08, 2006 page 745 of 982

REJ09B0054-0500

20.12 Power-Down States for Flash Memory

In user mode, the flash memory will operate in either of the following states:

• Normal operating mode

The flash memory can be read and written to at high speed.

• Power-down state

The flash memory can be read when part of the power circuit is halted and the LSI operates by

subclocks.

• Standby mode

All flash memory circuits are halted.

Table 20.6 shows the correspondence between the operating modes of this LSI and the flash

memory. When the flash memory returns to its normal operating state from standby mode, a

period to stabilize the power supply circuits that were stopped is needed. When the flash memory

returns to its normal operating state, bits STS2 to STS0 in SBYCR must be set to provide a wait

time of at least 100 µs, even when the external clock is being used.

Table 20.6 Flash Memory Operating States

LSI Operating State

Flash Memory Operating State

Active mode

Normal operating mode

Sleep mode

Normal operating mode

Watch mode

Standby mode

Subactive mode

Subsleep mode

PDWND = 0: Power-down mode (read only)

PDWND = 1: Normal operating mode (read only)

20.13 Flash Memory Programming and Erasing Precautions

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

programmer 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 flash memory on-chip microcomputer device type (FZTAT512V3A,

FZTAT256V3A, or FZTAT128V3A).

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