CoCopedia - The Tandy/Radio Shack Color Computer Wiki - User contributions [en]

Emulators

2026-05-29T00:39:10Z

TomHarte: /* Mac (pre OS X) */ Update Virtual CoCo link.

{{NavEmulators}}

For those who just want to relive some fond memories, an emulator is a great way to do just that.

= Online =

* [http://www.haplessgenius.com/mocha/ JS Mocha] - The HTML5 CoCo 2 Emulator
* [https://archive.org/details/basic-games-coco Vintage BASIC Games: Color Computer] - at archive.org, can be played directly in your browser
* [http://www.6809.org.uk/xroar/online/ XRoar Online] - Online Dragon/CoCo 1&2 emulator.

= Hardware =

== Raspberry Pi ==
* [http://www.780tech.com/cocopi3/ Ron Klein's CoCo Pi3 Project] - Use your Raspberry Pi3 as a CoCo and/or [[DriveWire]] server
* [http://coco-pi.com/ CoCo-Pi project] - a site dedicated to providing a complete CoCo 1,2,3 emulating environment on Raspberry 3 and 4 devices.
** [https://www.facebook.com/groups/748644118674047 CoCo-Pi] Facebook Group

== Adapters and peripherals==
* [[CoCo Joystick2USB Deluxe]] - An adapter to connect a TRS-80 Joystick (5/6-pin DIN) to a modern USB-capable computer
* [[CoCo Keys2USB Kit]] - Kit includes custom PCB, micro-controller, and connectors to build an encoder for connecting TRS-80 Color Computer 3/2 keyboard to USB port

= Emulators by Platform =

==Browser Based==
These emulators you can run directly from a web browser without needing to install anything:
* [http://www.haplessgenius.com/mocha/ Mocha], by Brad Grier, is a CoCo 1/2 emulator written in Java that runs from a web browser. This emulator has been running online for 10 years now and has a vast collection of disk and cassette programs to run.
* [https://www.6809.org.uk/xroar/online/ XRoar Online]

==Cross-platform==
* [http://rbelmont.mameworld.info/?page_id=163 MAME], the current version of MESS has been merge into MAME. MAME runs on Linux/Unix, Mac OS X, and other SDL-supported operating systems.
* [http://www.6809.org.uk/dragon/xroar.shtml XRoar] is a CoCo 1/2/3, MC-20 and [[Dragon]] emulator for Linux/Unix, Mac OS X, Windows, and other platforms.
* [http://www.github.com/TomHarte/CLK Clock Signal] is an emulator of various computers including the CoCo 1/2 for macOS and Linux/Unix.

== GNU/Linux==
* [[OVCC|The portable and open Virtual Colo(u)r Computer (OVCC)]] by [[Walter Zambotti]] aims to provide a native VCC version for GNU/Linux and macOS. Based on VCC by [[Joseph Forgione]].
* The Windows-based [[VCC]] emulator has also been shown to work under Linux using the WINE virtualization software.
* XRoar (see above under cross-platform).
* Clock Signal (see above under cross-platform).

==Mac (pre OS X)==
* [https://colorcomputerarchive.com/repo/Emulators/MacOS/Virtual%20Coco/ Virtual CoCo] - A CoCo 2 emulator for the Macintosh. Not much is known of this emulator.

==Mac OS X==
* [http://www.macmess.org/ MacMESS] - Multi-platform emulator that has a CoCo 1, 2 and 3 module. It is a front-end for [[SDLMESS]].
* OVCC (see above under GNU/Linux).
* XRoar (see above under cross-platform).
* Clock Signal (see above under cross-platform).

== PalmOS ==
* [http://www.colorcomputerarchive.com/coco/Emulators/Coco%201-2/Coconut/ CoCoNut] - CoCo 1/2 emulator for PalmOS v5 devices.

== MS-DOS ==
* Jeff Vavasour's CoCo emulator.

== Microsoft Windows ==

* [[MESS]] - Based on the MAME arcade emulator code, this project emulates various classic home computer systems.
* [[AdvanceMESS]]
* [[VCC]] - CoCo 3 emulator for Windows. (originally called "Bjork")
* XRoar (see above under cross-platform)

= Using Emulation (Tutorials) =

== General Information ==
* [[Working With Emulator Disk Images]]
* [[Using OS-9 on an Emulator]]
* [[Using XRoar]]

= ROM Resources =
Some places on the internet to download ROM and Disk images.
* A functional set of ROM images is included with the VCC emulator.

Emulators

2026-05-29T00:37:56Z

TomHarte: Expanded scope for XRoar, added Clock Signal.

{{NavEmulators}}

For those who just want to relive some fond memories, an emulator is a great way to do just that.

= Online =

* [http://www.haplessgenius.com/mocha/ JS Mocha] - The HTML5 CoCo 2 Emulator
* [https://archive.org/details/basic-games-coco Vintage BASIC Games: Color Computer] - at archive.org, can be played directly in your browser
* [http://www.6809.org.uk/xroar/online/ XRoar Online] - Online Dragon/CoCo 1&2 emulator.

= Hardware =

== Raspberry Pi ==
* [http://www.780tech.com/cocopi3/ Ron Klein's CoCo Pi3 Project] - Use your Raspberry Pi3 as a CoCo and/or [[DriveWire]] server
* [http://coco-pi.com/ CoCo-Pi project] - a site dedicated to providing a complete CoCo 1,2,3 emulating environment on Raspberry 3 and 4 devices.
** [https://www.facebook.com/groups/748644118674047 CoCo-Pi] Facebook Group

== Adapters and peripherals==
* [[CoCo Joystick2USB Deluxe]] - An adapter to connect a TRS-80 Joystick (5/6-pin DIN) to a modern USB-capable computer
* [[CoCo Keys2USB Kit]] - Kit includes custom PCB, micro-controller, and connectors to build an encoder for connecting TRS-80 Color Computer 3/2 keyboard to USB port

= Emulators by Platform =

==Browser Based==
These emulators you can run directly from a web browser without needing to install anything:
* [http://www.haplessgenius.com/mocha/ Mocha], by Brad Grier, is a CoCo 1/2 emulator written in Java that runs from a web browser. This emulator has been running online for 10 years now and has a vast collection of disk and cassette programs to run.
* [https://www.6809.org.uk/xroar/online/ XRoar Online]

==Cross-platform==
* [http://rbelmont.mameworld.info/?page_id=163 MAME], the current version of MESS has been merge into MAME. MAME runs on Linux/Unix, Mac OS X, and other SDL-supported operating systems.
* [http://www.6809.org.uk/dragon/xroar.shtml XRoar] is a CoCo 1/2/3, MC-20 and [[Dragon]] emulator for Linux/Unix, Mac OS X, Windows, and other platforms.
* [http://www.github.com/TomHarte/CLK Clock Signal] is an emulator of various computers including the CoCo 1/2 for macOS and Linux/Unix.

== GNU/Linux==
* [[OVCC|The portable and open Virtual Colo(u)r Computer (OVCC)]] by [[Walter Zambotti]] aims to provide a native VCC version for GNU/Linux and macOS. Based on VCC by [[Joseph Forgione]].
* The Windows-based [[VCC]] emulator has also been shown to work under Linux using the WINE virtualization software.
* XRoar (see above under cross-platform).
* Clock Signal (see above under cross-platform).

==Mac (pre OS X)==
* [http://www.colorcomputerarchive.com/coco/Emulators/Coco%201-2/Virtual%20Coco/ Virtual CoCo] - A CoCo 2 emulator for the Macintosh. Not much is known of this emulator.

==Mac OS X==
* [http://www.macmess.org/ MacMESS] - Multi-platform emulator that has a CoCo 1, 2 and 3 module. It is a front-end for [[SDLMESS]].
* OVCC (see above under GNU/Linux).
* XRoar (see above under cross-platform).
* Clock Signal (see above under cross-platform).

== PalmOS ==
* [http://www.colorcomputerarchive.com/coco/Emulators/Coco%201-2/Coconut/ CoCoNut] - CoCo 1/2 emulator for PalmOS v5 devices.

== MS-DOS ==
* Jeff Vavasour's CoCo emulator.

== Microsoft Windows ==

* [[MESS]] - Based on the MAME arcade emulator code, this project emulates various classic home computer systems.
* [[AdvanceMESS]]
* [[VCC]] - CoCo 3 emulator for Windows. (originally called "Bjork")
* XRoar (see above under cross-platform)

= Using Emulation (Tutorials) =

== General Information ==
* [[Working With Emulator Disk Images]]
* [[Using OS-9 on an Emulator]]
* [[Using XRoar]]

= ROM Resources =
Some places on the internet to download ROM and Disk images.
* A functional set of ROM images is included with the VCC emulator.

PIA

2026-05-18T15:25:58Z

TomHarte: Expand details on connections.

The '''Peripheral Interface Adapter''', formally the Motorola 6821, is a chip that provides two ports of parallel input and output plus control lines and interrupts. There are two in your CoCo, usually referred to as PIA0 and PIA1, and they're responsible for keyboard and joystick input, sound output and video mode selection and interrupt generation, amongst other tasks.

== Connections ==

=== PIA0 ===

Port A:
* b7: joystick comparison input;
* b0–b6: keyboard rows (b0 = row 0);
* b0 and b2: right joystick buttons (b0 = primary);
* b1 and b3: left joystick buttons (b1 = primary)
* CA1: the 6847's horizontal sync output;
* CA2: LSB of the MUX selection.

Since both keyboard rows and joystick buttons are connected to the low four bits, pressing joystick buttons can interfere with keyboard input.

Port B:
* b0–b7: keyboard column;
* CB1: the 6847's field sync output;
* CB2: MSB of the MUX selection.

PIA0's interrupt output is connected to the 6847's IRQ input.

=== PIA1 ===

Port A:
* b2–b7: DAC output level;
* b1: RS232 data output;
* b0: tape input;
* CA1: RS232 data carrier detect;
* CA2: tape motor control.

Port B:
* b7: 6847 alpha/graphics selection (0 = alphanumeric);
* b4–b6: 6847 graphics mode selection;
* b3: 6847 colour set selection;
* b2: RAM size;
* b1: 1-bit sound output;
* b0: RS232 data input;
* CB1: cartridge interrupt input;
* CB2: sound enable.

Cartridges short one of the clock pins onto their interrupt pin, which feeds into CB1 and therefore pulses every clock cycle; this is used by the machine to detect cartridge presence.

=== The MUX ===

The multiplexer selects both which joystick axis is enabled for comparison with the current DAC value and which source is currently selected for audio generation (if audio is enabled).

=== Keyboard ===

The keyboard can be scanned through PIA0 via addresses $FF00 (PIA0 port A data) and $FF02 (port B data). The first address ($FF00) represents keyboard rows as well as joystick buttons, and the second address ($FF02) keyboard columns; programs will normally set one of these as output and one of these as inputs, most normatively configuring $FF02 as output and using it to select which columns to scan and then reading $FF00 as input to very which rows on those selected columns had keys pressed. [[Color Basic]], when running a prompt, converts these to ASCII values to be printed to the screen at cursor position.

These two value correspond to ASCII values according to the following table:

{| class="wikitable"
|-
|
|0
|1
|2
|3
|4
|5
|6
|7
|-
|0
|@
|H
|P
|X
|0
|8
|Enter
|
|-
|1
|A
|I
|Q
|Y
|1
|9
|Clear
|
|-
|2
|B
|J
|R
|Z
|2
|:
|Break
|
|-
|3
|C
|K
|S
|Up
|3
|;
|
|
|-
|4
|D
|L
|T
|Down
|4
|,
|
|
|-
|5
|E
|M
|U
|Left
|5
| -
|
|
|-
|6
|F
|N
|V
|Right
|6
|.
|
|
|-
|7
|G
|O
|W
|Space
|7
|/
|Shift
|
|}

Keyboard layout is one of the few areas of hardware difference between a CoCo and a Dragon, other than video standard; the Dragon has the same physical layout as the CoCo but changes the column numbering — columns 6 and 7 are the same as the CoCo but everything else is off by 2. E.g. the CoCo's column 0 is the Dragon's column 2, the Coco's column 4 is the Dragon's column 6 and the CoCo's column 5 is the Dragon's column 0.

(under construction)

[[Category:Hardware]]

PIA

2026-05-18T14:46:01Z

TomHarte: /* Keyboard */ These are columns, not rows.

PIA

2026-05-18T14:44:51Z

TomHarte: Add some more detail, add keyboard map.