W77E058A Datasheet, PDF (74/87 Pages) Winbond – 8-BIT MICROCONTROLLER

W77E058A
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 W77E058 has a Special Setting Register, the Security Register, which can not be accessed in
normal mode. The register can only be accessed from the Flash EPROM 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 Security Register is addressed in the Flash EPROM operation mode by address #0FFFFh.
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