Try adding the following lines to your Init section:

ANSEL = 0x00;
ANSELH = 0x00;






-----Original Message-----
From: Gordon Downie <gordond1980@googlemail.com>
To: piclist@mit.edu
Sent: Fri, Jan 15, 2010 1:07 pm
Subject: [PIC]: Unable to read PORTB Bit 4, I'm doing something wrong..


Hi All,
I'm very new to PIC's and have started a small project where I want
he PIC18 to be an I2C slave. I am prototyping my design on the PICKit
 Low Pin Count Board with only the modifications described here.
PIC : PIC18F13K22 and PIC16F690 (Obviously with different code / toolchain)
ool Chain : C18 with MPLAB
Problem :
I was unable to get the I2C Slave HW to Ack address bytes sent by an
ardvark USB to I2C and after a week went back to basics. On the
rototype board I have removed the I2C connection (no other components
 connections) and Pulled RB4 and RB6 High via 33K resistors. I have
erified the resistance and voltage at the pin and both are correct
4.9v and 33kohm to Vdd), however when I read the port bits only RB6
s high. It does not matter which bit I read first. I've swapped out
o a different Chip and also switch to a different variant (PIC16F690)
nd re written the code below accordingly all with the same result so
'm confident I have missed something rather than a bad chip / board.
#include <p18f13k22.h>   /* for TRIS and PORT declarations */
#pragma config WDTEN = OFF
pragma config FOSC = IRCCLKOUT
pragma config PLLEN = ON
pragma config PCLKEN = ON
#pragma config MCLRE = OFF
pragma config LVP = OFF

pragma code
oid main (void){
   unsigned int b = 0;
    // OSC
   OSCCON = 0b11111100; // 8 MHz internal oscillator
    TRISC = 0x0;
   TRISB = 0xFF;
    PORTC = 0;
    TRISBbits.TRISB4 = 1;
   TRISBbits.TRISB6 = 1;
    while(1){
      //Display RB4 / RB6 on PORTC
       LATCbits.LATC0 = PORTBbits.RB4;
       LATCbits.LATC1 = PORTBbits.RB6;
        //Heartbeat
       b++;
       if (b==0) LATCbits.LATC3 = !LATCbits.LATC3;
   }


 am stumped. Any help / pointers gratefully received.
Many thanks,
ordon
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