W78IE52 Datasheet, PDF (11/22 Pages) Winbond – 8 BIT MICROCONTROLLER

Preliminary W78IE52
D7 D6 D5 D4 D3 D2 D1 D0
B7
Reserved B2 B1 B0
Security Bits
B0 : Lock bit, logic 0: active
B1 : MOVC inhibit,
logic 0: the MOVC instruction in external m emory
cannot access the code in internal memory.
logic 1: no restriction.
B2 : Encryption
logic 0: the encryption logic enable
logic 1: the encryption logic disable
B7 : Osillator Control
logic 0: 1/2 gain
logic 1: Full gain
Default 1 for all security bits.
Reserved bits m ust be kept in logic 1.
0000h
8KB Flash EPROM
Program Memory
Reserved
1FFFh
Security Register 0FFFFh
Special Setting Register
Lock bit
This bit is used to protect the customer's program code in the W78IE52. It may be set after the
programmer finishes the programming and verifies sequence. Once this bit is set to logic 0, both the
Flash EPROM data and Special Setting Registers can not be accessed again.
MOVC Inhibit
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.
Encryption
This bit is used to enable/disable the encryption logic for code protection. Once encryption feature is
enabled, the data presented on port 0 will be encoded via encryption logic. Only whole chip erase will
reset this bit.
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Publication Release Date: April 20, 2005
Revision A2