Connect the 4×4 keypad with port 1 of the microcontroller. Connect 16×2 LCD display with port 2 of the microcontroller (make sure that all the data pins of LCD display are connected to the microcontroller correctly). The rs (register set) pin of LCD is connected to pin 3.5 (pin number: 15) and en (enable) pin is connected to pin 3.6 (pin number 16) of the microcontroller. Connect crystal to pin 18 and 19 of the microcontroller. We are using 12MHz frequency Crystal. For reset, circuitry connects a pushbutton to pin 9 of the microcontroller. We can also use a potentiometer to adjust the contrast of LCD.
Regards ,
8051 Training in CETPA !!