Read MCU is a prevail technology in the industry of Electronic Product Reverse Engineering, Relevant protection mechanism has been established to protect MCU Read in the world. Asynchronous logic is a recently developed Read MCU 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 when Read MCU. 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 Read MCU, 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 when Read MCU. The main drawback of all these simple arrangement is they are very fragile: un-wanted HH status could emerge due to the circuit disadvantage when Read MCU.

Self-asynchronous design can be used to fend off the clock noise MCU reading. If the serial interface need clock, it is relatively easier to separate the clock from sensitive circuit. Power supply noise MCU read can seldom work on the asynchronous circuit, however, for those MCU with eeprom as memorizer won’t be protected and could be readed.

Dual Line design can obtain the alerting signals from sensor modification reliably, and constrain the operation of MCU. The final result could be the deletion of sensitive data from MCU and trigger the alert, it can prevent the flaw injection MCU read to gain success, MCU reader should inject two failure status simultaneously and make the status of transmitting line from LH switch to HL, which can cause the transmitting status enter into HH immediately and trigger the alert right away.