HD64F3337YCP16V Datasheet, PDF (490/749 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

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
Enable watchdog timer^*2
Select program mode
(P bit = 1 in FLMCR)
Wait (x) µs^*4
Clear P bit
Disable watchdog timer
Wait (t_VS1) µs^*5
Notes: *1 Use a byte transfer instruction.
*2 Set the timer overflow interval as
follows.
CKS2 = 0, CKS1 = 0, CKS0 = 1
*3 In prewrite-verify mode P, E, PV, and
EV are all cleared to 0 and 12 V is
applied to FV_PP. Read the data with
a byte transfer instruction.
*4 Programming time x, which is
determined by the inital time × 2^n–1
(n = 1, 2, 3, 4, 5, 6), increases in
proportion to n. Thus, set the initial
time to 15.8 µs or less to make total
End of
programming time 1 ms or less.
programming
*5 t_VS1: 4 µs or more
N: 6 (set N so that total
programming time does not
exceed 1 ms)
*6 Start and last addresses shall be top
and last addresses of the block to be
Prewrite verify^*3
(read data = H'00?)
OK
No go
n ≥ N?^*5
Yes
No
n+1→n
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
458
Address + 1→Address