w78l812a Winbond Electronics Corp America, w78l812a Datasheet - Page 17

• Manufacturer Part Number: w78l812a
• Description: 8-bit Mcu Series 80c51-based
• Manufacturer: Winbond Electronics Corp America

6.8.1
This bit is used to protect the customer's program code in the W78L812. It may be set after the
programmer finishes the programming and verifies sequence. Once this bit is set to logic 0, both the
on-chip ROM data and Special Setting Registers can not be accessed again.
6.8.2
This bit is used to restrict the accessible region of the MOVC instruction. It can prevent the MOVC
instruction in external program memory from reading the internal program code. When this bit is set to
logic 0, a MOVC instruction in external program memory space will be able to access code only in the
external memory, not in the internal memory. A MOVC instruction in internal program memory space
will always be able to access the ROM data in both internal and external memory. If this bit is logic 1,
there are no restrictions on the MOVC instruction.
Lock Bit
MOVC Inhibit
Default 1 for all security bits.
Reserved bits m ust be kept in logic 1.
D7 D6 D5 D4 D3 D2 D1 D0
B2 : Encryption
B0 : Lock bit, logic 0 : active
B1 : M OVC inhibit,
logic 0 : the encryption logic enable
logic 1 : the encryption logic disable
logic 0 : the M OVC instruction in external memory
logic 1 : no restriction.
Reserved
cannot access the code in internal m em ory.
B2
B1
B0
Special Setting Register
Security Bits
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Publication Release Date: November 6, 2006
W78LE812/W78L812A
8KB Flash EPROM
Program M emory
Security Register
Reserved
0FFFFh
0000h
1FFFh
Revision A9