• Presetting Configuration Fuses (PIC Defines) into your Program

    1. What are the Configuration Fuses?
    2. How can I preset them in my Program?
    2.a. When using MeLabs default (PM) Assembler
    2.b. When using Microchip's (MPASM) Assembler
    3. Where can I find a List of the Configuration Definitions?
    3.a. When using MeLabs default (PM) Assembler
    3.b. When using Microchip's (MPASM) Assembler



    1. What are the Configuration Fuses?

    The Configuration Fuses (Configuration Bits) are the settings that configure the PIC for the external environment it is expecting to find... typical settings include Oscillator Type, MCLR pin usage, Code Protection, Brown-Out and Watchdog Timer usage, Low Voltage Programming etc. Different families of PICs have different settings, so the list of settings for a 12F675, will not be the same as the list for a 16F877. When you LOAD a program into your programmer, these settings appropriately configure it without you having to make any additional changes. This saves you a lot of time messing with minor settings before you hit the 'Program' Button. Remember though, you are still able to over-ride these setting manually prior to programming your chip. Most programmers will only configure the settings to your compiled defaults when you LOAD the program, so if you change them manually, you will need to RELOAD your program for them to revert to the default (compiled) settings.


    2. How can I preset them in my Program?

    This very much depends on if you are using MeLabs default (PM) Assembler, or Microchips (MPASM) alternative.


    2.a. When using MeLabs default (PM) Assembler

    Example: To set the PIC for XT Oscillator...

    @ DEVICE XT_OSC

    or

    @ DEVICE PIC16F628,XT_OSC

    The PIC type is optional, if it is included and you accidentally compile for a chip other than that specified (a 16F628 in this example), the compiler will report an error as a reminder you're potentially doing something wrong.

    Multiple definitions are entered on separate lines, one line per definition and can be interspersed with comments…

    Example: Typical Settings for a 16F628…

    @ DEVICE pic16F628, INTRC_OSC_NOCLKOUT
    ' System Clock Options
    @ DEVICE pic16F628, WDT_ON
    ' Watchdog Timer
    @ DEVICE pic16F628, PWRT_ON
    ' Power-On Timer
    @ DEVICE pic16F628, MCLR_OFF
    ' Master Clear Options (Internal)
    @ DEVICE pic16F628, BOD_ON
    ' Brown-Out Detect
    @ DEVICE pic16F628, LVP_OFF
    ' Low-Voltage Programming
    @ DEVICE pic16F628, CPD_ON
    ' Data Memory Code Protect
    ' Set to CPD_OFF for Development Copy
    ' Set to CPD_ON for Release Copy
    @ DEVICE pic16F628, PROTECT_ON
    ' Program Code Protection
    ' Set to PROTECT_OFF for Development Copy
    ' Set to PROTECT_ON for Release Copy


    2.b. When using Microchip's (MPASM) Assembler

    Example: To set the PIC for Internal Oscillator allowing use of the OSC pins as I/O...

    @ __config _INTRC_OSC_NOCLKOUT

    Only one config statement is allowed when using MPASM, so multiple definitions follow-on from each other each connected to it’s previous buddy with an &.

    Example: Typical Settings for a 16F628…

    @ __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _BODEN_ON & _LVP_OFF & _CP_ALL & _DATA_CP_ON


    3. Where can I find a List of the Configuration Definitions?

    Now you’ll have noticed that my multiple example for PM and MPASM above are for the same configuration settings (they are now, they weren't when first posted!) - you’ll notice however that there are differences… MCLR_OFF in PM becomes MCLRE_OFF when using MPASM… Here’s how you find the list of possible options available to you… whether you chose to use the default PM or the option of the MPASM Assembler, cross-reference your choices with your chosen PICs Datasheet, look in the section entitled “Special Features of the CPU”. Some configurations may be listed under multiple names, the little extra being provided for your convenience.


    3.a. When using MeLabs default (PM) Assembler

    Open up the PBP directory, and in it you will find an INC subdirectory. Opening that up and you'll see a heap of files. Find the Mxxxx.INC file for the PIC you're interested in... (example M12F675.INC). If you can’t locate your exact PIC, it might be listed under a family of PICs that share the same settings (example chose M16F62X.INC if you need the settings for a 16F628). Open the file up with something like Notepad – (don’t make any changes to it) and have a look what the file contains…It reveals the internal sex life of the PIC. All the Configuration Fuse Defines that you can use from within PBP are listed here at the top, and lower down all the Registers are Listed. If it's not in the list, you can't use it - but trust me, it's usually all there. Remember, this list is for use with the PM (default assembler).


    3.b. When using Microchip's (MPASM) Assembler

    If you're going to use MPASM, look for the appropriate file (example for a 16F628 look for P16F628.INC) located in something like the MCHIP_Tools subdirectory of your MPLAB installation. Here you’ll find the Configuration Bits located near the bottom of the list. Simply just use the ones you want. Hey presto your PIC is all defined and ready to run.

    Melanie

    Below from Mister_e

    O.K. This is ask really often. Worth to be discussed NOW!

    What to do if i get "overwriting previous address content" error message?

    This error is return by PBP because your configuration fuse overwrite 'PBP default'. If you open with notepad, in PBP directory, the .INC file of your PIC, let's say 16F628, the file will look like this
    Code:
    ;**************************************************************
    ;*  16F628.INC                                                  *
    ;*                                                              *
    ;*  By        : Leonard Zerman, Jeff Schmoyer                   *
    ;*  Notice    : Copyright (c) 2002 microEngineering Labs, Inc.  *
    ;*              All Rights Reserved                             *
    ;*  Date      : 09/27/02                                        *
    ;*  Version   : 2.43                                            *
    ;*  Notes     :                                                 *
    ;**************************************************************
            NOLIST
        ifdef PM_USED
            LIST
            include 'M16F62x.INC'   ; PM header
            device  pic16F628, xt_osc, wdt_on, pwrt_on, mclr_on, lvp_off, protect_off
            XALL
            NOLIST
        else
            LIST
            LIST p = 16F628, r = dec, w = -302
            INCLUDE "P16F628.INC"   ; MPASM  Header
            __config _XT_OSC & _WDT_ON & _PWRTE_ON & _MCLRE_ON & _LVP_OFF & _CP_OFF
            NOLIST
        endif
            LIST
    So if you try to define HS oscillator, wich is already define, you'll overwrite the previous content of the PBP setting.

    To fix it, just comment those lines :
    Code:
    ;device  pic16F628, xt_osc, wdt_on, pwrt_on, mclr_on, lvp_off, protect_off
    OR
    Code:
    ;__config _XT_OSC & _WDT_ON & _PWRTE_ON & _MCLRE_ON & _LVP_OFF & _CP_OFF
    depending what you are using to compile your code, MPASM or PM.

    OR some will prefer to edit those line directly... as you wish...
    Where can i find the configuration fuse for my PIC ?

    All the configuration fuse are in the according .INC file located in the MPLAB directory. In MPLAB 7.01, the default directory, i suppose, is C:\Program Files\Microchip\MPASM Suite.

    If you open the appropriate .INC file, you will find all the configuration fuse for your PIC at the end of the file.

    looks like this for a 16F628...only the end
    Code:
    ;==========================================================================
    ;
    ;       Configuration Bits
    ;
    ;==========================================================================
    
    _BODEN_ON                    EQU     H'3FFF'
    _BODEN_OFF                   EQU     H'3FBF'
    _CP_ALL                      EQU     H'03FF'
    _CP_75                       EQU     H'17FF'
    _CP_50                       EQU     H'2BFF'
    _CP_OFF                      EQU     H'3FFF'
    _DATA_CP_ON                  EQU     H'3EFF'
    _DATA_CP_OFF                 EQU     H'3FFF'
    _PWRTE_OFF                   EQU     H'3FFF'
    _PWRTE_ON                    EQU     H'3FF7'
    _WDT_ON                      EQU     H'3FFF'
    _WDT_OFF                     EQU     H'3FFB'
    _LVP_ON                      EQU     H'3FFF'
    _LVP_OFF                     EQU     H'3F7F'
    _MCLRE_ON                    EQU     H'3FFF'
    _MCLRE_OFF                   EQU     H'3FDF'
    _ER_OSC_CLKOUT               EQU     H'3FFF'
    _ER_OSC_NOCLKOUT             EQU     H'3FFE'
    _INTRC_OSC_CLKOUT            EQU     H'3FFD'
    _INTRC_OSC_NOCLKOUT          EQU     H'3FFC'
    _EXTCLK_OSC                  EQU     H'3FEF'
    _LP_OSC                      EQU     H'3FEC'
    _XT_OSC                      EQU     H'3FED'
    _HS_OSC                      EQU     H'3FEE'
    
            LIST
    The 18F serie work different from the other. In the MPASM directory open the according .INC file. Look at the end you'll discover how to use the Config directive.

    Free example here...
    Code:
    @ __CONFIG _CONFIG1H, _OSCS_OFF_1H & _HS_OSC_1H
        ' Oscillator switch OFF
        ' Use HS oscillator (20MHZ here)
        '
    @ __CONFIG _CONFIG2L, _BOR_ON_2L & _PWRT_ON_2L & _BORV_45_2L
        ' Brown out reset ON @ 4.5Volts
        ' Power-up timer ON
        '
    @ __CONFIG _CONFIG2H, _WDT_ON_2H 
        ' Watch dog timer ON
        '
    @ __CONFIG _CONFIG4L, _STVR_ON_4L & _LVP_OFF_4L & _DEBUG_OFF_4L
        ' Stack over/underflow ON
        ' Low Voltage programming OFF
        ' Background debugger OFF

    Warning[230] __CONFIG has been deprecated for PIC18 devices.

    If you are using any PIC18 serie, you will have this warning one day or another. Our friends from Microchip decide to change the way to define the config fuses when using the latest MPASM version 5.00.

    From Darrel Taylor:
    Fortunately, the old __CONFIG directives still work. The __CONFIG has been deprecated warning, is just that. A warning. And Warnings can be turned off. So until Microchip decides to make it not work anymore, what I'm doing is to add this line to the .inc file for the chip it's being compiled for.
    Code:
        errorlevel -230
    Then everything works just like it always has.

    From Mister_e:
    don't forget to comment the PBP default fuse wich are located in the PBP folder in the according .INC file as Tissy found. So after the modification, Tissy's .INC file will looks like
    Code:
    ;****************************************************************
    ;*  18F2550.INC                                                 *
    ;*                                                              *
    ;*  By        : Leonard Zerman, Jeff Schmoyer                   *
    ;*  Notice    : Copyright (c) 2004 microEngineering Labs, Inc.  *
    ;*              All Rights Reserved                             *
    ;*  Date      : 12/31/04                                        *
    ;*  Version   : 2.46                                            *
    ;*  Notes     :                                                 *
    ;****************************************************************
            NOLIST
        ifdef PM_USED
            LIST
            "Error: PM does not support this device.  Use MPASM."
            NOLIST
        else
            LIST
            LIST p = 18F2550, r = dec, w = -311, f = inhx32
            INCLUDE "P18F2550.INC"    ; MPASM  Header
            ;__CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
            ;__CONFIG    _CONFIG1H, _FOSC_HS_1H
            ;__CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_128_2H
            ;__CONFIG    _CONFIG3H, _PBADEN_OFF_3H
            ;__CONFIG    _CONFIG4L, _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L
            NOLIST
        endif
            LIST
    EEPROM_START    EQU    0F00000h
    BLOCK_SIZE    EQU    32
    If you don't comment the default fuses... you'll always have this Warning message + another like overwriting previous content..



    This article was originally published in forum thread: Presetting Configuration Fuses (PIC Defines) into your Program started by Melanie View original post