keypad interface and scan

[internetuser2k11]

Hi!
I need a 4x1 keypad scan code for pic16f877a. I have attached the schematic.

4x1 keypad is connected to portb

Initial settings
OPTION_REG.B7 = 0; // all pull-ups enabled
TRISB = 0b00001111;

I don't want to use the keypad library.

I just need to scan the portb for 0b00001110, 0b00001101, etc...

I want to know with all pull ups enabled and B0 - B3 configured as Input and B4 - B7 configured as output. how to scan portb?

 

[engshahrul]

Don't know how to explain in English Language, I show in C Language below.

RB4=0;
keypad=PORTB&0b00001111;