PIC 16F877A Pin Out

Ports A and E become ANALOGUE INPUTS by default (on power up or reset), so they have to set up for digital I/O if required. Port B is used for downloading the program to the chip flash ROM (RB6 and RB7), and RB0 and RB4–RB7 can generate an interrupt. Port C gives access to timers and serial ports, while Port D can be used as a slave port, with Port E providing the control pins for this function.