12F683 - how to set it to use external 4 MHz clock?

[jimbostlawrence]

oooh further to my last I think I misunderstood what you said Dave... so I switched to the:

@ __config _XT_OSC & _WDT_ON & _MCLRE_ON & _CP_OFF

and now the error I get in the compiler is Error[118] e:\....\sertest.asm 93 : Overwriting previous address contents (2007)

?!

Is this perhaps related to my program and not this config aspect?

[mehmetOzdemir]

OPEN YOUR PBP FOLDER AND FIND 12F683.INC

YOU WILL SEE

NOLIST
    ifdef PM_USED
        LIST
        include 'M12F683.INC'	; PM header
        device  pic12F683, intrc_osc_noclkout, wdt_on, mclr_on, protect_off
        XALL
        NOLIST
    else
        LIST
        LIST p = 12F683, r = dec, w = -302
        INCLUDE "P12F683.INC"	; MPASM  Header
        __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_ON &_CP_OFF
        NOLIST
    endif
        LIST

CHANGE THE RED PART AFTER ELSE TO THIS ;

NOLIST
    ifdef PM_USED
        LIST
        include 'M12F683.INC'	; PM header
        device  pic12F683, intrc_osc_noclkout, wdt_on, mclr_on, protect_off
        XALL
        NOLIST
    else
        LIST
        LIST p = 12F683, r = dec, w = -302
        INCLUDE "P12F683.INC"	; MPASM  Header
        __config _XT_OSC & _WDT_ON & _MCLRE_ON & _CP_OFF
        NOLIST
    endif
        LIST

AND YOU DONT NEED TO WRITE "@ DEVICE" STATEMENT AT THE BEGINNING OF YOUR CODE ANYMORE.

[jimbostlawrence]

Excellent!!! I was just reading another persons similar problem and was trying to track it down. Many thanks for that. It does indeed now compile and MPLAB IDE lets me upload the code to the PIC.

Out of interest, is there any way that I can check if the thing has actually switched to the external oscillator [short of removing the oscillator!] by looking at the assembler file?

Many thanks all for help with this - has been bugging me for hours!

[mackrackit]

COOL!!!
You are using MPLAB!!!!
Tool bar - configure - configuration bits.
That shows the current sttings.

[jimbostlawrence]

Haha, you make it sound soooooooooo easy :P

'XT' Cheers

I was hoping that this would help with my serial comm's issue but it hasn't lol. Maybe try another PIC, one with a serial interface built in perhaps?!

I'll persist with this PIC for now and try to do some error-checking handshaking.

I can say that I've definitely learned something today

Best regards to all

J.

[mackrackit]

Now that the configs seem to be worked out, post your code and tell what is happening or not happening and we will see what can be done about it.

[jimbostlawrence]

Hi there,

I think I was having a Friday moment. It all seems to be working very well now that it's using the external osc'. I've even bumped up the baud rate to 9600 and getting a good response. Just putting together a simple algorithm to take input over the serial but and set the pulse frequency/duty cycle for HPWM via Hyperterminal.

Many thanks all for all your help. When I get the code done I'll post it on here as a working version. Won't be long.

Cheers

J.

[mackrackit]

In my opinion forget about using PM, always use MPASM. Later PM will nor work when you get into different things.

Now I forgot to tell you when you set the fuses in code space you will have to comment out some lines in the chips *.inc file that is in the PBP directory.
http://www.picbasic.co.uk/forum/showthread.php?t=543

Or you can modify the *.inc file.

My inc for this chip looks like this.

;****************************************************************
;*  12F683.INC                                                  *
;*                                                              *
;*  By        : Leonard Zerman, Jeff Schmoyer                   *
;*  Notice    : Copyright (c) 2005 microEngineering Labs, Inc.  *
;*              All Rights Reserved                             *
;*  Date      : 08/31/05                                        *
;*  Version   : 2.46a                                           *
;*  Notes     :                                                 *
;****************************************************************
        NOLIST
    ifdef PM_USED
        LIST
        include 'M12F683.INC'	; PM header
     ;   device  pic12F683, intrc_osc_noclkout, wdt_on, mclr_on, protect_off
        XALL
        NOLIST
    else
        LIST
        LIST p = 12F683, r = dec, w = -302
        INCLUDE "P12F683.INC"	; MPASM  Header
     ;   __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_ON & _CP_OFF
        NOLIST
    endif
        LIST