Extract MCU Memory Program is a prevail technology in the industry of Electronic Product Reverse Engineering, Relevant protection mechanism has been established to protect MCU unlocking flash and eeprom memory in the world.

Asynchronous logic is a recently developed MCU attacking protection technology, it has been introduced after the synchronous dual line logic promotion. As we all know, traditional digital logic use only one clock to synchronize the operation.

But accompany with acceleration of clock rate, this synchronized operation becomes more and more complicate. Due to this reason, it give rise to the self-synchronized or asynchronous design without the clock. There is one way is to use random technology on the data line to prevent MCU at89c51cc03 flash reading, in the dual line logic, signal zero and one is not high and low electrical press on single line anymore, but a pair of signal combination on the line.

Such as zero could probably LH, while one is probably HL, when in the application of synchronous circuit, LL signal means motionless. The main drawback of all these simple arrangement is they are very fragile: un-wanted HH status could emerge due to the circuit disadvantage.

One creative protection of MCU extract is using this flaw and takes HH as mistake signals. This signal can be acquired through sensor modification and cause the lock up of microcontroller at89c51cc01 flash reading. More interesting thing is the failure of MCU will stop the output of sensitive information which could probably the requirement for MCU with higher security level.

The other improvement of Dual-line coding is the decreasing of power consumption, makes all of the status with same weight. Dual line coding can’t completely ensure the power signal can be isolated from data, different circuit load will have different result, which can be controlled through the layout arrangement.