Prewrite-Verify Mode - Renesas F-ZTAT H8 Series Hardware Manual

Section 19 Flash Memory (H8/3048F: Dual Power Supply (V
Table 19.10 Watchdog Timer Overflow Interval Settings
Clock Frequency
10 MHz ≤ frequency ≤ 16 MHz
2 MHz ≤ frequency < 10 MHz
1 MHz ≤ frequency < 2 MHz
Note: The watchdog timer (WDT) set value is calculated based on the number of instructions
including write time and erase time from start to stop of WDT operation. In this program
example, therefore, no more instructions should be added between the start and stop of
WDT operation.
19.5.7

Prewrite-Verify Mode

Prewrite-verify mode is a verify mode used after writing 0 to all bits to equalize their threshold
voltages before erasure.
To program all bits, write H'00 in accordance with the algorithm shown in figure 19.11. Use this
procedure to set all data in the flash memory to H'00 after programming. After the necessary
programming time has elapsed, exit program mode (by clearing the P bit to 0) and select prewrite-
verify mode (leave the P, E, PV, and EV bits all cleared to 0). In prewrite-verify mode, a prewrite-
verify voltage is applied to the memory cells at the read address. If the flash memory is read in this
state, the data at the read address will be read. After selecting prewrite-verify mode, wait 4 µs
before reading.
Note: For a sample prewriting program, see the sample erasing program.
Rev. 7.00 Sep 21, 2005 page 624 of 878
REJ09B0259-0700
= 12 V))
PP
Variable
f
H'A57F
H'A57E
H'A57D