NOTE
-----

This is the "prog84" code modified to work with a serial port programmer,
and accept Intel code.

The serial port programmer is done as follows (wire colours are for
the two samples I have):

DB25 - DB9 - PIN

          (BLUE)                     +-----+
__   -   4 - DTR   ---------+--[>|---| L05 |--+----+----> Vdd (14)
          (blue)            |        +--+--+  |    |
                            |           |     |    | +
                            |           |     |  ===== 100uF
                          ===== 22uF   ///    |  =====
                          =====               |    |
                          + |      +----------+   ///
                            |      |
                            |      |   47K
                            |      +---XXXXX---* RUN
                            |                  *--------> /MCLR (4)
                            +------------------* PROG
                            |
                          __|_/
                         / / \  15v
                          /   \
                          --+--
         (WHITE)            |
      -  5  GND    ---------+---------------------------> Vss (5)
          (shield)   |
                    ///
                         4.7K          (GREEN) CLOCK
      -  7  RTS    ------VVVVV----+---------------------> RB6 (12)
                                  |    brown 
      -  2  RxD    ---------------+
                         4.7K          (ORANGE) DATA
      -  3  TxD    ------VVVVV----+---------------------> RB7 (13)
                                  |    black
      -  8  CTS    ---------------+


First, drive DTR high to power the PIC. It must stay high long enough
to charge the 100uF capacitor.

To reset the PIC, pull DTR low. /MCLR goes to -0.7v (the zener behaves
as a diode) and the 22uF capacitor charges to Vcc. Driving DTR active
again, voltage on /MCLR goes to ~2Vcc thus bringing the PIC into
programming mode (or run mode if the switch on the /MCLR line is set
accordingly).

Clock and data are generated by bit-bainging on RTS and TxD. Feedback
for the data line is available through CTS. The connection with RxD is
not useful during programming, but can serve if the PIC is talking
RS232 on RB6.

If programming lasts too long, the voltage on MCLR may drop below the
threshold for programming. In this case the PIC must be reset again
and programming restarted from the faulty location.

---------------------------------------
The original message follows.


WHAT IS THIS?							wiml@netcom.com
-------------							v0.9  26Dec1994

A PIC programmer. Specifically, I wrote this to program
  a PIC 16C84
  through the parallel printer port
  of a Linux box
  using the PIC's serial programming mode
  and a homebuilt programmer loosely based on David Tait's.

However, it uses a configuration file which should allow it to use almost
any parallel-port based programmer; and the low-level I/O is in a
separate file which could easily be replaced for operating systems
other than Linux.

This is *not* a "production" programmer; it doesn't do supply margining,
or probably a bunch of other things. However, you have the source,
so you can make it do whatever you want.

This release is stable enough that I'm using it for my own tinkering
with PICs and am doing development basically only when I discover
it won't do something I want it to do. It should work out of the
box on a Linux system, but it's not for the technically faint of heart
(but then, if you're not comfortable mucking about with the
system when it misbehaves, why are you running Linux?) 

If you make modifications or improvements, PLEASE send them to me so
that I can maintain a coherent master copy and hopefully integrate
everything into a portable, versatile, bulletproof driver.

INSTALLATION
------------

Just type 'make'. The executables must be setgid kmem to run from a
normal account; the Makfile will prompt you for the root password
so it can do this. If you don't like that, enter a garbage password
and setgid them yourself.

On non-Linux machines, you will probably have to replace io_ports.c
with whatever is appropriate to your system. This file contains
routines to implement basic byte I/O by reading and writing
/dev/port. On operating systems with no hardware protection (DOS,
Windows, ...), you can just use inb() and outb().  Please send let me
know about any changes you have to make to get this to work with your
setup.

You will need to create an lp_cfg file to tell these programs how
to work with your hardware. See either the man page (prog84.man)
or the old README file for details.

MANIFEST
--------

README			This file.
prog84.man		A man page for prog84.
old-README		A README file from a previous revision of these
			programs. Contains some useful information.
Makefile		The makefile, of course.

progmain.c		Top-level routines for prog84.
prog84.[hc]		High-level routines for programming a 16C84.
lp_io.c			Buffered parallel-IO routines.
io_ports.[hc]		Low-level I/O routines.

lp_cfg			A sample configuration file.
schematic.ps		Schematic diagram for the simple programmer with
			which the sample configuration file works.

jig.c			A tool to allow you to interactively clock
			bits through the '84.
lpttool.c		A tool to allow you to write values to the parallel
			port and read the status register.
dump.c			Simple program to read out part of the '84's
			code and data.


--------

Written by Wim Lewis: wiml@netcom.com or wiml@hhhh.org.