16f688 and MCLR (ra3) as input

[kitcat]

Ok so I know that I have to set RA3 as an input and disable the MCLR function. I see that it also has a weak pull up which can be disabled. How can I set RA3 as an input, i.e. disable the MCLR and weak pull up. I have tried looking everywherre. Can I do it in code?

Thanks

Matt

[mister_e]

everything will be done with config fuses. See the end of your .Inc files in the MPLAb directory

it looks like this

;==========================================================================
;
;       Configuration Bits
;
;==========================================================================

_FCMEN_ON                    EQU     H'3FFF'
_FCMEN_OFF                   EQU     H'37FF'
_IESO_ON                     EQU     H'3FFF'
_IESO_OFF                    EQU     H'3BFF'
_BOD_ON                      EQU     H'3FFF'
_BOD_NSLEEP                  EQU     H'3EFF'
_BOD_SBODEN                  EQU     H'3DFF'
_BOD_OFF                     EQU     H'3CFF'
_CPD_ON                      EQU     H'3F7F'
_CPD_OFF                     EQU     H'3FFF'
_CP_ON                       EQU     H'3FBF'
_CP_OFF                      EQU     H'3FFF'
_MCLRE_ON                    EQU     H'3FFF'
_MCLRE_OFF                   EQU     H'3FDF'
_PWRTE_OFF                   EQU     H'3FFF'
_PWRTE_ON                    EQU     H'3FEF'
_WDT_ON                      EQU     H'3FFF'
_WDT_OFF                     EQU     H'3FF7'
_LP_OSC                      EQU     H'3FF8'
_XT_OSC                      EQU     H'3FF9'
_HS_OSC                      EQU     H'3FFA'
_EC_OSC                      EQU     H'3FFB'
_INTRC_OSC_NOCLKOUT          EQU     H'3FFC'
_INTRC_OSC_CLKOUT            EQU     H'3FFD'
_EXTRC_OSC_NOCLKOUT          EQU     H'3FFE'
_EXTRC_OSC_CLKOUT            EQU     H'3FFF'
_INTOSCIO                    EQU     H'3FFC'
_INTOSC                      EQU     H'3FFD'
_EXTRCIO                     EQU     H'3FFE'
_EXTRC                       EQU     H'3FFF'

you'll have to write a line to define your config fuse. Choose _MCLRE_OFF

How to do that? click here

Probably you'll have this message 'overwriting previous content....'
use notepad, open 16F688.inc in your PBP directory. looks like this

;****************************************************************
;*  16F688.INC                                                  *
;*                                                              *
;*  By        : Leonard Zerman, Jeff Schmoyer                   *
;*  Notice    : Copyright (c) 2003 microEngineering Labs, Inc.  *
;*              All Rights Reserved                             *
;*  Date      : 11/06/03                                        *
;*  Version   : 2.45                                            *
;*  Notes     :                                                 *
;****************************************************************
        NOLIST
    ifdef PM_USED
        LIST
        include 'M16F688.INC'	; PM header
        device  pic16F688, intrc_osc, wdt_on, mclr_on, protect_off
        XALL
        NOLIST
    else
        LIST
        LIST p = 16F688, r = dec, w = -302
        INCLUDE "P16F688.INC"	; MPASM  Header
        __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_ON & _CP_OFF
        NOLIST
    endif
        LIST

cooment the 'device' or 'config' line and you're i business.

OR modify within this file and forget the define in your code... i

[peterdeco1]

Hello Matt. I just did the exact thing with a PIC16F819. I'm sure it works for them all. At the top of your code put:

@ DEVICE MCLR_OFF

Or you can manually turn it off on the programming software. Hope this helps.