>I've been trying to program an '84, preferably via RS232. I've tried
>several schematics (some parallel instead), and have intermittant
>results.

Did You try it on another PC ?
Maybe Your PC or its power supply produces too much noise.
I've tried several LPT and RS232 schematics and all worked fine.

>
>I have two schematics that I'm particularly fond of (because I'm trying to
>integrate the programmer into the final "product", and these lend
>themselves to it well). If anyone has used either of these and/or can give
>me helpful hints as to what problems they've found, I would much
>appreciate it. If anyone knows of a "better" circuit (i.e. one that's
>simple, that has freely available software for programming it, and it
>works), I'd love to know.

I've integrated my version of an RS232 programmer into an 16C84 module.
(Looks like a Basic Stamp).

>I first tried the RS232 circuit that runs under PIP. Its schematic is
>available from ftp://rasi.lr.ttu.ee/pub/SIS/CAD/DIY/BITMAPS/com84.gif. It
>looks like the serial info is getting to the pic; however, I don't know
>enough about the programming timing to tell if it's working correctly or
>not. PIP-02 (with pinapi driver installed) goes through the motions, and
>reports "Error Programming Device!".

The schematic is correct, but it seems that some versions of the 78L05
power regulator draw too much current from the port.
I've used Zener diodes in my design.



 TxD -----*-------------------------I
          I                         I
          I                         I
         ---                       ---
         I I  2k2                  I I  10k
         I I                       I I
         ---                       ---
          I   I\I                   I
          *---I I----*--------I     I
          I   I/I    I        I     I
         ---\        I +      I     I
     5V6 / \        ---       I     I
         ---        --- 100u  I     I
          I          I        I 14  I 4
          I          I     I--I-----I---I
          I          I     I Vdd   Vpp  I
          I          I   5 I            I
GND ------*----------*-----I Gnd        I
                           I            I   PIC 16C84
        22k                I            I
        --              12 I            I
RTS ---I  I----------------I RB6        I
        --                 I            I
        --              13 I            I
DTR ---I  I---*------------I RB7        I
        --    I            I            I
        2k2   I            I------------I
              I
CTS ----------I




This should work.
If not, try to connect a small capacitor (10-1000pF) between Vpp and GND.
I can send You my TP source, if You want.

>
>#2.
>I've tried the blowpic program and its related circuit:
>
>;                                                       PC Power Supply
>;                                PIC16C84
>;    Parallel Port Pin          .--------.     Switch /o----- GND
>;                   (2)  D0  ---{13     4}----------o/ o----- +12V
>;                   (3)  D1  ---{12    14}--------.
>;                               |   5  16}-+-%%%%-`--- +5V
>;                               `----+---' |   2.2K Resistor (*)
>;                                    |    =*= 10uF Capacitor (*)
>;                   (25) GND --------`-----`---------- GND
>;

This should work under all circumstances.
Except if You are using a non compatible parallel port.
That leads me back to the distortion theory.
Try to use another PC !


 - Erik