Restore Winbond W78IE54 MCU Encrypted Heximal

As we all know that in the common situation, the status of a MCU W78IE54 will be set as encrypted, and only through disable the security fuse bit can Restore Winbond W78IE54 MCU Encrypted Heximal. hereby we would like to introduce the security system of W78IE54:

During the on-chip MTP-ROM programming 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.

special setting register

The W78IE54 has several Special Setting Registers, including the Security Register and Company/Device ID Registers, which can not be accessed in programming mode before Restore Winbond W78IE54 MCU Encrypted Heximal. 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. The Security Register is located at the 0FFFFH of the LDROM space.

Lock bit
This bit is used to protect the customer’s program code in the W78E62B. It may be set after the programmer finishes the programming and verifies sequence. Once this bit is set to logic 0, both the MTP ROM data and Special Setting Registers can not be accessed again.

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