Introduction - If you have any usage issues, please Google them yourself
SCM locks source code and schematics: 4* 3 keypad with numeric keys and the Enter key consisting of 0 to 9, the delete key with 8 digital tube display circuit message composition, when a password, only " -" When the password digits have been entered, press enter, and set the initial password password input comparison, if the password is correct, then unlock, then P3.0 port LED (ie yellow) light for one second as a reminder if the password is incorrect, prohibit the importation 3 seconds, an alarm sounds at the same time. The initial password is eight. New feature: external interrupts 0 and 1 respectively, to achieve a reset and password change function