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GAL-F4 Project: Port F4 for MSX2-to-MSX2+ Upgrading
Copyright (c) 2024-2025 HotPixel and RBSC
Last updated: 16.03.2025
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About
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By the end of 2024 there were 2 different project for creating port F4 on MSX computers in order to convert them to MSX2+.
These projects were:

 - The port F4 board by Caro: https://github.com/Wierzbowsky/F4_Board
 - The combo FPMAC/F4 board by RBSC: https://github.com/RBSC/F4-FMPAC

Both projects required several logic ICs and additional components to be installed on their boards. Once there was a need
to convert an MSX computer to MSX2+, HotPixel decided to create a simplier solution based on a single PAL chip. The solution
was created and tested; later Wierzbowsky [RBSC] created and tested the circuit board for this solution.

More information on port F4 could be found here: https://map.grauw.nl/resources/msx_io_ports.php#sysflags


Assembling notes
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Please read the following notes carefully:

 - The GAL chip must be programmed BEFORE being soldered onto the circuit board

 - The pins of GAL chip must be shortened so that they don't stick out on the bottom side of the board

 - The soldering of GAL chip must be done on the TOP side of the board, the bottom side of the board must be kept flat

 - The board must be placed on top of Z80 CPU; it's good to put some thermal paste onto the Z80

 - Pins must be installed only in holes that are marked by white dashes - no need to solder all 40 pins

 - The installed pins must touch respective pins of Z80 CPU; then pins must be soldered to the circuit board and to Z80 pins


Testing the board
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When the Z80 CPU with the board is installed into the converted MSX2+ computer with MSX2+ BIOSes and SubROM, it's very easy
to test the solution. When powering on a computer, there must appear the MSX logo. Pressing RESET button (warm boot) will
result in booting the computer without the MSX logo. If MSX logo is displayed after pressing the RESET button, the board is
not working properly


IMPORTANT!
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The RBSC provides all the files and information for free, without any liability (see the disclaimer.txt file). The provided
information, software or hardware must not be used for commercial purposes unless permitted by the RBSC. Producing a small
amount of bare boards for personal projects and selling the rest of the batch is allowed without the permission of RBSC.

When the sources of the tools are used to create alternative projects, please always mention the original source and the
copyright!


Contact information
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HotPixel has a Youtube channel: https://www.youtube.com/@HotPixel

The members of RBSC group Tnt23, Wierzbowsky, Pyhesty, Ptero, GreyWolf, SuperMax, VWarlock, Alspru and DJS3000 can be
contacted via the group's e-mail address:

info@rbsc.su

The group's coordinator could be reached via this e-mail address:

admin@rbsc.su

The group's website can be found here:

https://rbsc.su/
https://rbsc.su/ru

The RBSC's hardware repository can be found here:

https://github.com/rbsc

The RBSC's 3D model repository can be found here:

https://www.thingiverse.com/groups/rbsc/things

-= ! MSX FOREVER ! =-