Troubleshooting/Modifying your Serial PIC programmer

The graphical schematics shown on Anitti's page are drawn for a 9-pin serial connection. The pin-pin translation is shown below:


  9 pin      -       25 pin

    3                 2
    5                 7
    7                 4
    4                 20
    8                 5

If your programmer does not work, you may want to try some of these hints:

to reduce confusion for those of you in the western hemisphere, 4K7 is equivalent to 4.7K
the value of the diode is not very important. Any small signal diode should work.
From the ground pin, run a ground wire to the metal chassis of the hood.
Place a small (12 pf?) capacitor between the ground and TXD pin.
Make sure you are using a 78L05 not a 7805. The 7805 consumes the precious few millivolts/amps necessary to drive the circuit.
I think the resistor pot was placed between CTS and DTR (pins 4 & 8)

Is your serial port just too weak to put out 10-12V? Thanks Atle! Try this:

Date: Mon, 16 Sep 1996 17:28:48 +0200 (MET DST)
From: Atle Silgjerd 
To: rxy5310@hertz.njit.edu
Subject: PIC-Blaster tip

Thank you for a great programmer. I had some problems getting
it started because the serial port of my computer did not give
more than 9-10V. Since the programming voltage should be
about 12-13 V, I just put two AA cell batteries (2x1.5V) in series with
the line to the reset pin (pin 4). I had to break the circuit
between the diode and pin 4 and solder wires to the batteries
which were tied to the circuitboard with a rubberband (remember to
isolate the metal surface of the battery from the circuit !)

I have found these to solve some problems with "finicky" serial ports.
Good luck. Have fun.

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 Rolan Yang            http://hertz.njit.edu/~rxy5310   Electrical Engineer
 rxy5310@hertz.njit.edu                             kyurius@tsb.weschke.com
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