Current Microtan 65 emulator

I am actively developing a newer Microtan 65 emulator for Linux and WSL2. It is a working project, but remains under development.

The emulator models the main Microtan 65 board and chunky graphics, a 7 KB Tanex with two 6522 VIAs, sound hardware, a 64 KB RAM board, ASCII keyboard, hex keypad and joystick input. Display options include four Tangerine high-resolution boards, the Mousepacket Colour VDU and an experimental 256×256 indexed-colour graphics board.

TAN-DOS and firmware

The optional TAN-DOS controller emulation provides eight logical drives (0: to 7:) backed by raw disk images. Images can be mounted read/write or read-only and changed while the emulator is running; the card state and mounted images are retained in the settings file. The supplied master image should normally be mounted read-only.

The standard firmware image contains modified BASIC D3, XBUG and TANBUG v3B. TANBUG v3B supports both the standard display and the Colour VDU and includes the TANBUG v3.1 TAN-DOS commands. The original firmware image remains in the repository for historical use and regression testing.

The disk-controller implementation covers the normal seek, step, sector read/write, address-read and interrupt operations needed to use TAN-DOS. Low-level track formatting is not yet emulated, so blank raw images are created by the emulator and then initialised from TAN-DOS.

ETI real-time clock

The emulator also implements the real-time clock/calendar card published as a Microtan project in Electronics Today International in April 1983. It uses the article’s example address range, $BC30–$BC3F, and models the MM58174A’s BCD registers, timed interrupts and tenth-of-a-second update indication.

By default, the emulated card follows the host computer’s local time. Programs can stop the clock, set its date and time, and restart it; the resulting offset from host time is retained in the emulator settings. A Microtan reset does not reset this battery-backed clock state.

Files and controls

The emulator loads my .m65 snapshot format and Intel HEX files (.hex, .ihx and .ihex). Its persistent menu bar provides access to files, system controls, disks, displays, input devices and help. Function keys open the menu and emulated keyboards, while F5 resets the processor. The numeric keypad Enter key acts as the Microtan LINEFEED key.

Serial I/O, complete hex-keypad behaviour and parts of the experimental graphics board remain unfinished. The repository is therefore the authoritative source for current capabilities and limitations.

Visit the Microtan 65 repository on GitHub

• Read the TAN-DOS emulator and disk-image notes on GitHub
• Read the ETI real-time clock implementation notes on GitHub
• Read the experimental graphics-board register specification on GitHub
• Browse the archived hardware manuals on this site

Use GitHub for the source code, current build instructions, issue tracking and latest project status. The repository and its binaries are not copied into this website.