[PIC] PIC18F4550 PORTB.B7 always returns 1

[Alloy]

Hey.
Why this code:

void main() {
   OSCCON =  0X70;       // Set internal oscillator at 8MHz
   ADCON1 = 0x0F;        // Configure AN pins as digital

 UART1_Init(9600);
 
 
 // enable weak pull-ups on port B
 INTCON2.RBPU = 1;
 
 TRISB.F7 = 1;    //Configure RB7 as input (PGD)
 while(1){
         if(PORTB .B7)
         {
                    UART1_Write_Text("0");
         }
         else
         {
                    UART1_Write_Text("1");
         }
         Delay_ms(500);
 }

}

always prints 1?
I have disconnected the programmer..
I have button on RB7...
and button does not work...

 

[mvs sarma]

as per datasheet following programming of B port helps
CLRF PORTB ; Initialize PORTB by
; clearing output
; data latches
CLRF LATB ; Alternate method
; to clear output
; data latches
MOVLW 0Eh ; Set RB<4:0> as
MOVWF ADCON1 ; digital I/O pins
; (required if config bit
; PBADEN is set)
MOVLW 0CFh ; Value used to
; initialize data
; direction
MOVWF TRISB ; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs

 

[FvM]

RBPU bit is low active, you'll write 0 to it to enable pull-ups. Code should work apart from this point.

 

[betwixt]

...and, because you are pulling it up, the switch must be connected to ground!

Brian.