Preliminary W78E51B
Company/Device ID Read Operation
This operation is supported for MTP ROM programmer to get the company ID or device ID on the
W78E51B.
OPERATIONS P3.0 P3.1 P3.2 P3.3 P3.6 P3.7
(A9 (A13 (A14 (OE
CTRL) CTRL) CTRL) CTRL)
P2,P1
P0
NOTE
EA
(A15..A0) (D7..D0)
(VPP)
(CE) ( OE )
Read
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
1
0
1
Address Data Out
Output Disable
Program
1
X
Hi-Z
Address Data In
Address Data Out @3
VCP
VCP
Program
Verify
Erase
1
0
0
0
0
1
VEP
A0:0,
others: X
Data In
0FFH
@4
Erase Verify
1
0
0
0
0
0
0
1
1
0
1
VEP
Address Data Out @5
Program/Eras
e Inhibit
X
VCP/
VEP
X
X
Company ID
Device ID
Notes:
1
1
0
0
0
0
0
0
0
0
0
0
1
1
A0 = 0 Data Out
A0 = 1 Data Out
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 MTP-ROM cells and the Security bits.
5. The erase verify operation follows behind the erase operation.
SECURITY BITS
During the on-chip MTP-ROM operation mode, the MTP-ROM can be programmed and verified
repeatedly. Until the code inside the MTP-ROM is confirmed OK, the code can be protected. The
protection of MTP ROM and those operations on it are described below. The W78E51B has several
Special Setting Registers, including the Security Register and Company/Device ID Registers, which
can not be accessed in normal mode. These registers can only be accessed from the MTP-ROM
operation mode. Those bits of the Security Registers can not be changed once they have been
programmed from high to low. They can only be reset through erase-all operation. The contents of the
Company ID and Device ID registers have been set in factory. Both registers are addressed by the A0
address line during the same specific condition. The Security Register is addressed in the MTP-ROM
operation mode by address #0FFFFh.
- 10 -
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