Bill Brendling's version of MEMU

Introduction

Andy Key's MEMU is an extremely effective, feature rich, and flexible emulator for the Memotech MTX series of computers, without which none of the following would have been possible. One of the consequences of MEMU's flexability is that running the program requires supplying a number of command line switches to specify the details of the emulation required. A number of potential users find this offputting, this was reiterated at the last Memofest meetup. There are a number of possible solutions to this issue:

• It is possible to create a number of batch files (Windows) or command scripts (Linux) which run MEMU in a specific emulation mode.
• Paul Daniels has produced a version of Gamebase which can be used to run many MTX games.
• I wrote a Python based Launcher which can start MEMU in a number of standard emulation modes. However this does not support all the MEMU features.

When I first started playing with MEMU one of my main objectives was to turn a Raspberry Pi computer into a "Bare Metal" emulation of the MTX. This means no operating system and therefore no command line from which to specify the required switches. Therefore I had to provide a system for setting the configuration from within MEMU. Again I went for the option of providing a few "typical" configurations rather than supporting all of the options that MEMU can provide. I therefore added the option of a configuration dialog as shown:

While originally developed for the "bare metal" version, the dialg can also be included in Windows or Linux versions of MEMU, which may be of interest for the reasons given above.

My version of MEMU has also acquired a few other features which have not yet been included in Andy's version:

• The configuration dialog, as above. By default the initial configuration is read from "memu.cfg" in the same folder as the program executable. Changes made with the configuration dialog are saved back into this file. An alternative configuration file may be specified using the -config-file option on the command line. Other options may be specified on the command line as per Andy's MEMU. (Windows, Linux & Raspberry Pi)
• Loading programs from or saving to audio (*.wav) files instead of data (*.mtx) files. This provides one way of developing a program on MEMU and then transferring it to a real MTX (or vice-versa). (Windows, Linux & Raspberry Pi)
• Emulation of the CFX-II addon, including the Propeller VGA display. (Windows, Linux & Raspberry Pi)
• Running Fuzix (a Unix/Linux clone). This relies upon the CFX-II emulation. (Windows, Linux & Raspberry Pi)
• Enhanced keyboard remapping to improve the usability of MEMU with modern keyboards. This follows the approach used for the PC keyboard interface, and allows the keyboard mapping to be changed dynamically, using the <Scroll Lock> and <Num Lock> keys. (Windows, Linux & Raspberry Pi)
• Using a real serial port to emulate the MTX serial port. This allows multiple machines running MEMU to be connected in a NODE ring. This has been tested with a Raspberry Pi connected to an x86 PC. It should be possible to similarly connect MEMU to a real MTX, but this has not been tested. (Linux only, including Raspbian)
• Use of Raspberry Pi GPIO to connect MEMU to real hardware, including keyboard, joystick and printer. (Raspberry Pi including bare metal)
• Use of Raspberry Pi GPU to accelerate MEMU display. (Raspbian only)

Conversely, my version can be a year (or more) behind the latest features added to Andy's version.

For convenience I have created a number of distributions:

• Runtime for Microsoft Windows (32 bit).
• Runtime for x86 Linux (32 bit).
• Runtime for Raspbian (or other 32 bit Linux distributions on Raspberry Pi).
• Bare Metal Runtime for Raspberry Pi.
• Source code (can build all versions).

Distributions

Microsoft Windows Runtime

memu.exe

This is the classic command line version of MEMU.

memu-cfg.exe

This is the version of MEMU with configuration dialog.

To install, simply unzip the distribution into a suitable location, perhaps "Program Files (x86)". It may be worth creating a desktop shortcut, pointing to "memu-cfg.exe", with the working folder set to the folder containing the program.

Linux (x86) Runtime

memu

This is the classic command line version of MEMU.

memu-cfg

This is the version of MEMU with configuration dialog.

The other two are for use from the console, without X-Window, and display full screen. Use <Ctrl> plus the function keys to switch between VDP display and 80-column display:

memu-fb

This is the command line version of MEMU using full-screen frame buffer.

memu-cfb

This is the configuration dialog version of MEMU using full-screen frame buffer.

To install, unzip the file into s suitable location. Optionally copy the contents of the "memu" folder into a location on the path, such as "/usr/local/bin".

Raspbian Runtime

memu-pi

This version of MEMU is intended for use from the console, without X-Window. It displays full-screen, using the Raspberry Pi GPU. It can also use the GPIO to interface to real hardware.

Bare Metal Runtime

This distribution contains the bare metal version of MEMU (with configuration dialog), compiled for different versions of the Raspberry Pi. At present the following are NOT supported:

• Running on a Raspberry Pi model 4B
• Serial port (DART) emulation
• GPU acceleration

Source Distribution

• Pressing both the <Alt> keys and then releasing them reboots the emulation. The reboot actually happens when the first of the keys is released. In CFX emulation, selecting a mode requires holding another key down while rebooting. Depending upon the operating system being used, try either of the following:
  • Press and hold one <Alt> key. Press and hold the required letter key. Press and release the second <Alt> key. Release the first <Alt> key. Release the letter key after a few seconds.
  • Press and hold both <Alt> keys. Press and hold the required letter key. Release the <Alt> keys. Release the letter key after a few seconds.
• If keyboard mapping is enabled, then the following keys influence the mapping applied:
  • If <Scroll Lock> is off, then the keys exactly as on the MTX are emulated. This will work with all MTX software, but means that for some symbols you have to press a differently labelled key on the PC keyboard. See here for details. If <Scroll Lock> is on, then keys which do not exist on the real MTX are emulated to produce characters matching the symbols on the PC keyboard. The MTX ROM and CP/M are patched to recognise these additional keys, but they will not work with any software which has its own keyboard driver.
  • If <Num Lock> is off, to assist game play, the PC numeric keypad is mapped to the MTX keypad by key position. However this means that the keypad keys do not produce the numbers shown on the keys. If <Num Lock> is on, then the mapping is changed so that the numeric keypad produces the expected numbers.
  On some operating systems, it is not possible to ensure that the keyboard LEDs match the lock state as seen by MEMU. If keys are not producing the expected result it is therefore worth changing the lock states.

Within the configuration dialog, if "Audio Tapes" is turned off ("No") then only binary (*.mtx) tape files can be selected. In this mode, tape files will load very quickly. If "Audio Tapes" is turned on ("Yes"), then either binary (*.mtx) or audio (*.wav) tape files may be selected. However all files will be slow to load (realistic speed), and you will hear an approximation of the tape loading sounds. Binary files are effectivly converted back to audio in order to load them. Audio files in other formats such as *.mp3 must be converted to *.wav before they can be used.

The supplied disk images are in a number of sizes:

• Files with an extension of "*.mfloppy" or "*.mfloppy-07" are 640KB type 07 floppy disk images which may be used as B: or C: disks in SDX or CP/M emulations.
• Files with an extension of "*.img" are 8MB CP/M partitions. They may be used as either Compact Flash partitions (types 18 to 1F) or Silicon Disks (type 4F).
• "ht.bin" is a large data image used by Hextrain. It is not readily accessible to other MTX software.
• "fuzix.drive" is an image of a multi-partition drive, for booting Fuzix.

Typical configuration for SDX emulation

The image below shows a typical configuration for SDX emulation, with a tape file ready for loading with the command LOAD "", and a disk of games available for USER LOAD "game". Any user programs can be saved with USER SAVE "name"

Typical configuration for CP/M emulation

A typical configuration for CP/M emulation, with two floppy disks, is shown below.

Typical configuration for CFX-II emulation

For the CFX-II it is necessary to open a sub-dialog to select the files to form partitions on the emulated Compact Flash cards. To open this dialog, select the Compact Flash card on the main dialog, and then use <Space> or <Enter> to open the sub-dialog.

Hextrain configuration

Hextrain is Andy Key's incredible MTX game with 3D graphics. To run this, set the configuration as shown and restart. Once CP/M has started type the command "hextrain" (renamed from "htsi"), and then switch to the VDP window or display.

Fuzix configuration

Fuzix is a Unix like operating system for Z80 machines. It has been ported to the MTX with CFX-II storage add-on, and can be run in MEMU. To run it, set the configuration as shown:

Restart, then once the CFX-2 startup page is showing, reboot using the two <Alt> keys with the "C" key down, as if rebooting to CP/M. Fuzix will begin to boot. When prompted for "bootdev:", enter "hda1" (without the quotes). Enter the date and time when requested. Finally login as "root". When finished using Fuzix, enter the command "shutdown" to cleanly unmount the emulated drives and halt the system. Otherwise a lengthy check of drive integrity will be required next time Fuzix is started.

Command Line Versions

Most of the command line usage is as per Andy Key's Documentation which is repeated here.

The additional options for my version are:

The configuration dialog version also uses the same swiches, storeing them in the configuration file, but they may also be given on the command line. There are a few additional switches listed below to support the operation of the dialog.

And finally, two further switches specific to the Raspberry Pi specific versions: