HD64F3437TF16 Datasheet, PDF (491/752 Pages) Hitachi Semiconductor – 12 V must not be applied to the S-mask model (single-power-supply specification), as this may permanently damage the device.

Prewrite Flowchart
Start
Set erase block register
(set bit block to be programmed to 1)
Set start address^*6
n=1
Write H'00 to flash memory
(flash memory latches write address
and write data)^*1
Notes: *1 Use a byte transfer instruction.
*2 Set the timer overflow interval as
follows.
CKS2 = 0, CKS1 = 0, CKS0 = 1
Enable watchdog timer^*2
*3 In prewrite-verify mode P, E, PV,
and EV are all cleared to 0 and
Select program mode
(P bit = 1 in FLMCR)
12 V is applied to FV_PP. Read the
data with a byte transfer instruction.
*4 Programming time x, which is
Wait (x) µs^*4
determined by the inital time × 2^n–1
(n = 1, 2, 3, 4, 5, 6), increases in
proportion to n. Thus, set the initial
Clear P bit
Disable watchdog timer
End of
programming
time to 15.8 µs or less to make total
programming time 1 ms or less.
*5 t_VS1: 4 µs or more
N: 6 (set N so that total
programming time does not
Wait (t_vs1) µs^*5
exceed 1 ms)
*6 Start and last addresses shall be top
and last addresses of the block to be
erased.
Prewrite verify^*3
No go
(read data = H'00?)
No
n ≥ N?^*5
OK
n+1→n
Yes
Double programming time
(x × 2→x)
Last address?^*6
No
Yes
Clear erase block register
(clear bit of programmed block to 0)
Programming error
End of prewrite
Figure 20.10 Prewrite Flowchart
462
Address + 1→Address