if the keypad is connected to | Electronics › Electronics › some questions about the project “Electronic code lock with user defined password using 8051 microcontroller (AT89C51)” › if the keypad is connected to May 10, 2011 at 6:49 pm #6142 SaLMAN Ahmed KhanParticipant if the keypad is connected to PORT 0 OF 8051 then you must need to connect these resistors as they work as pull up …… but you can use the other port to interface keypad .
