Hi all,
Been beating my brain for a couple of days on this. Writing some 'c' code to program a pic microcontroller.
Windows was blocking my output on com2. Here's how I fixed it, nowhere on the internet have I found this
solution.

1. rename the msports.inf in \windows\inf\msports.inf to msportssave.inf
2. rename the serial.vxd in \windows\system\serial.vxd to serialsave.vxd
3. Go into control panel and delete the serial under port system/device manager/ports
4. Reboot, windows will find the ports but won't be able to find a driver, just continue and the ports will be added
to other devices in system/device manager.
5. You can now access the serial ports directly
6 I restored com1 to windows status by renaming the msports.inf file and serial.vxd to original names. Deleted
com1 and rebooted, windows finds com1 and loads the windows drivers and I can still use com2 for my program.
YEEEHAWWWW

Hope this helps others
James Luttrell
JTL-Consulting
jimbo@jimbo.kicks-ass.org

Introduction

 This is Revision E of the 16F84 to 12C509 porting checklist. Many on the PIClist have contributed, but a record has not been kept. The checklist is intended to be used when moving working code from one processor to the other, and as a guide for things to avoid when writing code that one day may be moved.

 A source template for assembly code that can be used on both processors is included.

Legend

Checklist

• include P12C509A.INC instead of P16F84.INC in source,
• check __CONFIG flags,
• use of MCLRE,
• no use of PWRTE,
• valid oscillator configuration,
• if not using _MCLRE_OFF,
• check GP3 is not used,
• if using _IntRC_OSC,
• clock may drift, check any external timing assumptions,
• check first instruction is MOVWF OSCCAL,
• check 0x3ff is not to be programmed (contains MOVLW for OSCCAL),
• if using JW part (quartz windowed erasable), save OSCCAL from 0x3ff and program,
• instructions not available,
• check code for no use of instructions SUBLW, ADDLW, nor RETFIE,
• check use of RETLW instead of RETURN, [Dwayne Reid]
• peripherals not available,
• check code for no use of register addresses EEDATA, EEADR,PCLATH,INTCON,EECON1, nor EECON2,
• port and TRIS latches,
• check code for no use of register addresses PORTA,PORTB,
• substitute GPIO for PORTB, same address (0x06),
• no use of TRISA nor TRISB register addresses,
• use of TRIS instruction required,
• general register file access,
• check register file addresses used do not exceed limits (valid range is 0x07 to 0x1f and 0x30 to 0x3f, addresses below 0x0c are in use on 16F84 anyway, so this is the first common free address),
• check code for FSR register,
• ensure MSB of FSR is not used, [Marc Hoffknecht]
• FSR bit 5 must be zero for direct access to file registers in the range 0x00-0x1f, and must be one for 0x30-0x3f.
• special register file addresses,
• built-in registers,
• check code for no use of STATUS bits IRP,RP1, nor RP0,
• check code for OPTION_REG register,
• no use of OPTION_REG,
• use of OPTION instruction,
• no use of OPTION_REG bits RBPU nor INTEDG,
• T0CS bit must be '0' if GP2 is output, [Michael Ghormley]
• CALL/RETLW usage
• check stack depth does not exceed two levels, [G. Daniel]
• CALL can only work to addresses 0x000-0x0ff,
• CALL can only work to addresses 0x200-0x2ff if PA0 set,
• use a vector table if entry points are outside these ranges,
• GOTO usage
• GOTO works for 0x000-0x1ff normally,
• GOTO can only work to addresses 0x200-0x3ff if PA0 set,
• ADDWF to PCL can only work to 0x000-0x0ff, or 0x200-0x2ff if PA0 set.

Template

        ifdef           __16f84
        processor       16f84
        include         "p16f84.inc"
        __config        _cp_off & _wdt_on & _hs_osc
        endif

        ifdef           __12c509
        processor       12c509
        include         "p12c509a.inc"
        __config        _mclre_off & _cp_off & _wdt_on & _intrc_osc
        endif
        
        ifdef   __16f84
base    equ     0x0c            ; first free file register address
port    equ     portb           ; port on which bits are used
movwt   macro                   ; move w to tris
        tris    trisb
        endm
bank0   macro
        endm
bank1   macro
        endm
        endif

        ifdef   __12c509
base    equ     0x07            ; first free file register address
port    equ     gpio            ; port on which bits are used
movwt   macro                   ; move w to tris
        tris    gpio
        endm
page0   macro                   ; select low bank for goto/call
        bcf     status,pa0
        endm
page1   macro                   ; select high bank for goto/call
        bsf     status,pa0
        endm
        endif

        cblock  base
                ephemeral       ; temporary storage
                ...
        endc

        ;; start of executable code
        
        org     0x0

        ifdef   __12c509
        movwf   OSCCAL          ; calibrate internal oscillator
        endif
        page1
        goto    main            ; go to main program
        ...



        ;; calibration for 12C509-JW part
        ifdef   __12c509
        org     0x3ff
        movlw   0x50                    ; my 12c509 #1
        ; movlw 0x30                    ; my 12c509 #2
        endif

        end

Be sure tocheck for the latest version at:
http://quozl.us.netrek.org/porting-16f84-12c509/
and advise us if it has been updated.

_
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