W78E54B Datasheet, PDF (10/21 Pages) Winbond – 8-BIT MICROCONTROLLER

W78E54B
OPERATIONS P3.0 P3.1 P3.2 P3.3 P3.6 P3.7 EA P2, P1
P0 NOTE
(A9 (A13 (A14 (OE _{( CE ) ( OE )} (VPP) (A15..A0) (D7..D0)
CTRL) CTRL) CTRL) CTRL)
Read
0
0
0
0
0
0
1 Address Data Out
Output Disable 0
0
0
0
0
1
1
X
Hi-Z
Program
0
0
0
0
0
1 VCP Address Data In
Program Verify 0
0
0
0
1
0 VCP Address Data Out @3
Erase
1
0
0
0
0
1 VEP A0:0, Data In @4
others: X _0FFH
Erase Verify
1
0
0
0
1
0 VEP Address Data Out @5
Program/Erase X
0
0
0
1
1 VCP/
X
X
Inhibit
VEP
Notes:
1. All these operations happen in RST = VIH, ALE = VIL and PSEN = VIH.
2. VCP = 12.5V, VEP = 14.5V, VIH = VDD, VIL = Vss.
3. The program verify operation follows behind the program operation.
4. This erase operation will erase all the on-chip Flash EPROM cells and the Security bits.
5. The erase verify operation follows behind the erase operation.
SECURITY BITS
During the on-chip Flash EPROM operation mode, the Flash EPROM can be programmed and verified
repeatedly. Until the code inside the Flash EPROM is confirmed OK, the code can be protected. The
protection of Flash EPROM and those operations on it are described below.
The W78E54B has a Security Register which can not be accessed in normal mode. These registers
can only be accessed from the Flash EPROM operation mode. Those bits of the Security Register can
not be changed once they have been programmed from high to low. They can only be reset through
erase-all operation. The Security Register is addressed in the Flash EPROM operation mode by
address #0FFFFh.
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