Adapter

The 87x51, and 89x52 Microcontrollers in the [Options/Device] offer an additional option allowing one to program Lock Bits and the Encryption Array.

If Lock Bit 1 is programmed, the Microcontroller's internal EPROM can no longer be read out using the program (with the MOVC instruction). If both Lock Bits are programmed, reading out the EPROM using the programming device is also no longer possible.

If the Option Encryption Table is enabled, the 32 (or 64) bytes following the data area of the buffer are programmed as encryption bytes. The start point of the encryption table depends on the EPROM capacity of the Microcontroller one uses, but the following table may serve as a reference point:

PLEASE NOTE: When reading out devices with programmed encryption tables, the encrypted data will be read and then written to the buffer.

Background: Every EPROM byte refers to one encryption byte derived from the address module 32 (or 64). When reading out the internal EPROM using a programming device, the data will be linked to the pertinent encrypted byte XOR to ensure that the content of the memory cannot be decrypted without knowledge of the encryption array.