PIC 16C84 Serial mode programmer, hardware.                  
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The programmer is connected to a parallel printer port of a PC. 
It uses the serial programming method which uses two signals
(data and clock) to communicate with the PIC. 
D0 of the parallel port is used for Data, D1 is for Clock.
D2 switches the MCLR/Vpp pin and D3 is used for switching
the power supplied to the PIC on and off. The Busy signal is
also connected to Data to read data from the PIC. Together with
GND six pins are used from the parallel port.

A 7407 open collector non-inverting buffer seperates the PIC from
the parallel port. There are two LEDs, Power and Activity.
Power indicates that the programmer gets enough power. It
should always be on. Activity indicates that power is applied 
(5V and Vpp) to the PIC. This is under control of the programmer 
software. You can try this without a chip by reading the chip
contents. The software will think that is sees an empty chip since 
there is no way of telling if a chip is inserted or not. 
(An empty chip will always read ones.)
When the Activity LED is off PIC may be inserted or removed.
Never insert a PIC when it is on.

Building the programmer is pretty straightforward. I made 
a little box (7 x 5 x 2 cm) with an 18 pin ZIF socket and
the circuit. Connecting the box to a parallel port could 
be done with a 6 lead RJ-12 cable. There are these neat 
D25 connectors with an RJ-12 connector on the back...
You could use RJ-10 for the power-connections. Power
can come from an AC-adaptor that gives at least 15V.
(Most 12V adaptors will do.) I left the capacitors out, 
spread a few around where apropriate, but don't make them
too large.

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The ingredients for the programmer are:
 
 1 x 78L05               Voltage regulator 5V, 100 mA
 1 x 78L12               Voltage regulator 12V, 100 mA
 1 x 7407                Open collector non-inverting buffers
 1 x ZIF socket 18 pin   Can be expensive   
 2 x Transistor PNP      e.g. BC 557 
 2 x LED                 Red 3 mm
10 x Resistor 10k
 2 x Resistor 1k
 1 x Diode               Anti-smoke-and-fire
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The ASCII drawing of the programmer follows on next page.

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                                                  +5V
 15..30V                                           |14
                  +-------+                     +--+--+
V+ ]--|>|---+-----+ 78L05 +--- +5V              | 7407|    
            |     +---+---+                     +--+--+
            |         |                            |7      
            |        GND                          GND
            |     +-------+               A   K
            +-----+ 78L12 +--- +12V ------[LED]------[1k]----GND
                  +---+---+              "Power"
V- ]--- GND           |
                     GND                  A   K
                                Vpp ------[LED]------[1k]----GND
                                       "Activity"
                                                      Vdd
                                                       |14
                          Vdd-[10K]--+       +---------+--------+
                  1|\  2             |     13|                  |
  D0 (2)-----------+  >--------------+-------+ RB7/Data         |
                   |/                |       |                  |
      +5V-[10k]-+                    |       |                  |
                | 12 /|13(corrected) |       |    PIC 16C84     |
Busy (11)-------+--<  +--------------+       |     18 pin       |
                     \|                      |    ZIF Socket    |
                           Vdd-[10k]--+      |                  |
                  3|\  4              |    12|                  |
   D1 (3)----------+  >---------------+------+ RB6/Clock        |
                   |/                        |                  |
                           Vpp-[10K]--+      |                  |
                  5|\  6              |     4|                  |
   D2 (4)----------+  >---------------+------+ -MCLR/Vpp        |
                   |/                        |                  |
                                             +---------+--------+
                                                       |5
                                            +5V       GND
                                             |
                                  +--[10K]---+
                                  |          |
                 11|\  10         |      B |/ E
             +-----+  >----[10K]--+--------|     PNP
             |     |/                      |\ C
             |                               |
             |                               +---Vdd
             |                               |
             |                             [10K]
             |                               |
             |                              GND
             |
             |                              +12V
             |                               |
             |                    +--[10K]---+
             |                    |          |
             |    9|\  8          |      B |/ E
   D3 (5)----+-----+  >----[10K]--+--------|     PNP
                   |/                      |\ C
                                             |
                                             +---Vpp
  GND (19)------GND                          |
                                           [10K]
                                             |
                                            GND
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