After I got tired asking friends for flashing my Minimig with the closed
source Windows tool "Tinybld" I found an open source project for Linux
called "tinyul". It's just the uploader, reengineered from Tinybld, but
what more do we need? I ported the Linux source to NetBSD and soon realized
that an Amiga port wouldn't be much more difficult.

About Tinybld: The "Tiny PIC Bootloader" by Claudio Chiculito is a small
boot loader program for dsPIC, 16F- and 18F-series PICs which resides
in the last 200 bytes of a PIC's flash memory. It allows flashing itself
via RS-232 (serial interface). The program used for communicating with
the tiny boot loader is called Tinybld and only available for Windows.
The Minimig is just one of many devices using the tiny boot loader.
http://www.etc.ugal.ro/cchiculita/software/picbootloader.htm

About Tinyul: The "Tiny Uploader". A command line based replacement for
Tinybld written by Thomas Themel for Linux.
http://wiki.themel.com/tinyul


INSTALLATION

Copy the program (and icon) for your prefered architecture anywhere you want.
Look into the directory AmigaOS3, AmigaOS4 or MorphOS.


USAGE

You need the Magic User Interface from Stefan Stuntz. Plain old V19
(MUI 3.8) is sufficient: http://aminet.net/util/libs/mui38usr.lha.
MorphOS and AmigaOS4.x already have a recent MUI version installed.

You may start TinyulMUI either by clicking its icon on the Workbench or
from command line. The latter also allows you to pass the name of the
file to upload as an optional parameter.

Before you can flash any PIC you need to enter:

1. The configuration for your serial interface.
   The serial.device unit 0 with 115200 bps is preconfigured by default,
   which usually works fine for AmigaOS3 and MorphOS. For AmigaOS4 you
   will have to change the device name to a1serial.device or
   pegserial.device (or whatever your hardware supports).
   Also you might want to change the device settings when you have a
   3rd-party serial board (like MFC, etc.) in the 68k-Amiga. 115200 bps
   are required by Minimig.
   When the serial interface was successfully opened the "Check PIC"
   button becomes available.

2. The path to the file to upload.
   Tinyul accepts Intel-Hex (ihex) files, which are common for PICs. Upon
   entering its name the file will be parsed and checked for errors. When
   everything is ok (checksums are correct) the "Upload file" button
   becomes available.

Now TinyulMUI offers you two possible actions:

Check PIC: The ATTN byte (0xc1) is sent, which the PIC has to reply with
its identification byte and a handshake. When the identification represents
a supported PIC type its name will be printed. The progress bar shows when
the maximum number of retries is reached.

Upload file: This will flash the PIC with the selected ihex file.
It includes a "Check PIC", before flashing can start. The current state of
the flashing process is shown by a progress bar. It can take a few seconds.

Other settings:
The timeout defaults to 500ms, which is the time Tinyul will wait for
an acknowledge from the PIC. An acknowledge takes place after sending
the identification byte and after every 64-byte block being transfered.
The number of retries (10 by default) and "Ignore garbage chars" has only
a meaning during "Check PIC".

I tested the program on all the three supported architectures with success.
MorphOS with serial.device and AmigaOS4 with pegserial.device on a
Pegasos2/G3, and the AmigaOS3 version on an A3000 with 68060/50.
Flashing the Minimig's PIC (18F252) works very reliable for me.
No other PICs were tested!

Theoretically Tinyul supports the following PIC types:
  16F876A/16F877A
  16F873A/16F874A
  16F87/16F88
  18F252/18F452/18F2520/18F4520
  18F242/18F442/18F2420/18F4420
  18F258/18F458
  18F248/18F448
  18F1320/18F2320
  18F1220/18F2220
  18F4320
  18F4220
  18F6720/18F8720
  18F6620/18F8620
  18F6520/18F8520
  18F8680
  18F2525/18F4525
  18F2620/18F4620
  18F2550/18F4550
  18F2455/18F4455


WARNING

A 68060 CPU had no problem to keep up with 115200 bps transfer rates, but
you have to be careful with slower CPUs. The transfer might fail in the
middle because of lost characters and wrong checksums.

In the case of the Minimig a half-finished upload should be no problem, as
I was told that the boot loader usually stays operational.

But, nevertheless, I take no responsibility when you brick your device
with TinyulMUI!


HISTORY

V1.0 (31-Dec-09):
After two days of hard work. Just in time before New Year and for the
latest Minimig updates from Christmas.

V1.1 (02-Jan-10):
Improved the MUI code with some help from Gianfranco Gignina (ShInKurO).
Fixed a listview problem which made all output disappear after resizing
the window. Make sure the scrollbar is always moved to the last entry.


For bug reports, suggestions, etc. contact Frank Wille (frank@phoenix.owl.de).

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
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[generic]                11301   20164  56.0% -lh5- 3d2a Jan  2 14:12 aos68k/tinyulMUI
[generic]                 2437    3170  76.9% -lh5- a3b4 Dec 31 19:19 aos68k/tinyulMUI.info
[generic]                16280   42940  37.9% -lh5- 1928 Jan  2 14:12 aosppc/tinyulMUI
[generic]                 2437    3170  76.9% -lh5- a3b4 Dec 31 19:19 aosppc/tinyulMUI.info
[generic]                 2394    4895  48.9% -lh5- a528 Dec 31 18:49 CVS/Base/tinyulMUI.readme
[generic]                15418   41112  37.5% -lh5- 6790 Jan  2 14:06 morphos/tinyulMUI
[generic]                 2865    2865 100.0% -lh0- 02d5 Dec 31 18:52 morphos/tinyulMUI.info
[generic]                 2510    5097  49.2% -lh5- 5ff3 Jan  2 14:25 tinyulMUI.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         8 files   55642  123413  45.1%            Jan  2 10:47