Hello Byon,

>    I've been programming PICs for quite some time with a modified Tait
programmer
> and modified PP.EXE code.  By tri-stating the MCLR line (0V/5V/13V),  the
> modification allowed me to switch the PIC from program to run in software
so I could
> assemble, program, and run with a single batch file. In moving to 16F87X
parts, I'm
> ready to build a new dev environment.
>
>   I've noticed that the FPP.EXE code has a Run button.  Does anyone know
if this
> button works like my modified programmer?  If so, which programmer
hardware will
> allow switching from program to run in circuit without human intervention?
Also,  I
> have not yet experimented with LVP PIC programming.  Does this allow for
in-circuit
> program/run?

    I'm still looking for a programmer that can tristate the MCLR line. I
don't know why these (being so simple and usefull) isn't adequately
supported by any programmer (software or hardware) I've found.

    I think that before programming, MCLR should be pulled LOW for resetting
the PIC and setting RB6/7 to inputs (high impedance) if they're configured
as outputs. Then, the MCLR should go to 13V and start programming.

    PICAllW and FPP both have an additional line (RESET on PICAllW, MCLR on
FPP), but it's toggled for the entire programming circle and can't be used
to ensure a reset just prior to start programming.

    PICAllW (with P16PRO, as I'm using) still works correctly (if you just
put a 10K resistors from MCLR pin to VDD and if you use the RB6/7 just for
key inputs with RBPU enabled) with PIC16F parts, but it's giving me big
headaches with the PIC18F parts.

    IC-PROG seens to have provision for a MCLR and a VPP line, but I don't
know how it works and haven't found a supported programer that uses it.

    We'll have to continue looking for it.

    Best regards,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Research and Development               Blumenau  -  SC  -  Brazil
Say NO to HTML mail                          www.citronics.com.br
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