On Thu, Feb 28, 2002 at 12:28:47PM -0600, Pic Dude wrote:
> So I read up on bank selection and added it, but still can't get port A
> to be inputs.  Now, if I try port C as inputs, that also does not work.
>
> This is what I have for port C...
>
>     LIST P=16F872
>     INCLUDE "p16f872.inc"
>     ERRORLEVEL -224
>     __CONFIG _PWRTE_ON & _RC_OSC & _WDT_OFF & _LVP_OFF
>
>     ORG 0
>
>     bcf STATUS,RP0    ; Bank0...
>     bcf STATUS,RP1    ;    ...bank0
>     clrf PORTC
>     bsf STATUS,RP0    ; Bank1
>     movlw 0x06
>     movwf ADCON1      ; Port A all digital
>     movlw 0x0F
>     movwf TRISC       ; Port C -- only RC0:RC3 are inputs.
>
>     movlw B'00000000'
>     movwf ADCON0      ; Turn off A/D
>     movwf TRISA       ; Port A is all outputs
>     movwf TRISB       ; Port B is all outputs
>
> loop:
>     movf PORTC,0
>     movwf PORTB
>
>     goto loop
>
>     end
>
>
> Inputs are connected to pins 11,12,13,14.  LED's at all 8 RB's.
>
> Possibilities -- I'm missing something fundamental here.

Yup. You forgot to switch back to bank 0 after doing your moves to the TRIS
registers. So your loop is operating in Bank 1.

> I fried the chip during one of the previous mis-configurations.

>  However, I tried
> downloading walk.asm again and it works (though only outputs).  Is it possible
> to fry only part of a PIC?

Yes. But that isn't your problem. Bank management is a PITA with PICs. But
the bookkeeping must be done.

BAJ
>
> Thanks,
> -Neil.
>
> --
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>

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