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Prewrite Flowchart
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Start
Address = top address
Set
V
E
bit
PP
V
E
(
bit = 1 in FLMCR)
PP
Wait (z) µs
Set erase block register
(set bit of block to be erased to 1)
n = 1
Wait initial value setting x = 15 µs
Write H'00 to flash memory
(flash memory latches
write address and write data)
Enable watchdog timer
Select program mode
(set P bit to 1 in FLMCR)
Wait (x) µs
Clear P bit
Disable watchdog timer
) µs
Wait (t
VS1
Prewrite verify
*3
(read data = H'00?)
OK
Last address?
Yes
Clear erase block register
(clear bit of block to be erased to 0)
Clear
V
E
bit
PP
End of prewrite
Notes: 1. Use a byte transfer instruction.
*1
*2
Programming ends
No good
n ≥ N?
Clear erase block register
(clear bit of block to be erased to 0)
Clear V
Programming error
No
Figure 18-17 Prewrite Flowchart
596
2. Set the watchdog timer overflow
interval by setting CKS2 = 0,
CKS1 = 0 and CKS0 = 0.
3. In prewrite-verify mode P, E, PV,
and EV are all cleared to 0 and
12 V is applied to V
. Use a byte
PP
transfer instruction.
4. t
: 4 µs
VS1
z:
5 to 10 µs
N:
6 (set N so that total
programming time does not
exceed 1 ms)
No
n + 1
Yes
Double
the programming
time (x × 2 → x)
E bit
PP
Address + 1 → address
→ n
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