Datasheet

Table Of Contents
Section 19 Flash Memory (F-ZTAT Version)
Page 654 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
19.8.2 Erase/Erase-Verify
When erasing flash memory, the erase/erase-verify flowchart shown in figure 19.12 should be
followed.
1. Prewriting (setting erase block data to all 0s) is not necessary.
2. Erasing is performed in block units. Make only a single-bit specification in the erase block
register 1 (EBR1), and erase block register 2 (EBR2). To erase multiple blocks, each block
must be erased in turn.
3. The time during which the E1 bit is set to 1 is the flash memory erase time.
4. The watchdog timer (WDT) is set to prevent overprogramming due to program runaway, etc.
An overflow cycle of approximately (y+z+α+β) ms is allowed.
5. For a dummy write to a verify address, write 1-byte data H'FF to an address whose lower 1 bit
is B'0. Verify data can be read in words from the address to which a dummy write was
performed.
6. If the read data is unerased, set erase mode again, and repeat the erase/erase-verify sequence as
before. The maximum number of repetitions of the erase/erase-verify sequence is N.