CDTV Technical Information

by Darren Ewaniuk
Last Updated July 5, 1997 *NEW*

Leave EMail to if you experience any problems or wish to have any additions to this page.

Quick Links within this document:
[Introduction] [Peripherals] [Software Tricks] [Workbench 2] [Memory Map] [Hardware Pinouts] [Hardware Hacks] [Manufacturers] [Acknowledgments]


I've done a number of hardware hacks for the CDTV, and have been frequently answering technical questions about it. I've been wanting to try writing a "real" web page, and think a technical info FAQ about the CDTV would both provide me with some experience, and the Amiga community with some useful information. So here it is.

CDTV Peripherals:

The CDTV comes without much in the way of peripherals. It can be expanded to about the equivalent of an A500. Here is a list of some peripherals that work for the CDTV:

* Display:

* Floppy Drive Port:

* Serial Port:

* MIDI IN and OUT Ports:

* Parallel Port:

* Keyboard:

* Joystick/Mouse Controller Port:

* Memory Card:

* DMA Expansion Slot:

* Internal Expansion Options:

Software Tips and Tricks

Front Panel Time Display

The front panel time display on the CDTV is controlled by the clock chip on the CDTV. The clock chip is refreshed by the main power as long as the power cord is plugged in, whether the CDTV's power switch is on or off (not a battery like the A500 or A2000 clock). Otherwise it is the same chip in the same memory location as a standard A500 or A2000 clock.
To change the display for your own programs, all you have to do is write the time to the clock registers (see the A500/A2000 Technical Reference Manual). Of course, in doing this, you change the backed up time as well, so when you're done, you probably should restore the clock from the system time (I.E. using setclock save).

CDTV Memory Map

000000-0FFFFF Chip memory
100000-1FFFFF Space for extra chip memory (Megachip)
200000-9FFFFF Space for AutoConfig memory
A00000-BFFFFF CIA chips
C00000-C7FFFF Space for slow-fast memory
C80000-DBFFFF Space
DC0000-DC7FFF Power backed-up real time clock
DC8000-DC87FF Non-volatile RAM
DC8800-DCFFFF Space in non-volatile RAM decoded area
DD0000-DEFFFF Space
DF0000-DFFFFF Custom chips
E00000-E7FFFF Memory card address space for front panel memory card
E80000-E8FFFF AutoConfig configuration space
E90000-E9FFFF First AutoConfig device, used by DMAC
EA0000-EFFFFF Space for other AutoConfig devices
F40000-F7FFFF Space in CDTV ROM decoded area
F80000-FBFFFF Space in Kickstart ROM decoded area (used by Kickstart 2)
FC0000-FFFFFF Kickstart ROM

Workbench 2 and the CDTV

The CDTV uses a standard 16-bit Kickstart 1.3 ROM in socket U13, exactly the same as the ROM in a 2000 or 500, with an additional pair of 8-bit EPROMs in sockets U34 and U35 containing the CDTV-specific code such as the audio player and the CD-ROM filesystem.

The CDTV-specific code wedges into the Kickstart 1.3 ROMs and executes on startup. Because of some changes made to Kickstart 2, the CDTV code does not start up correctly, thus the 2 Kickstart ROM will not work, even though it is electrically compatible with the old Kickstart 1.3 ROM.

Official solution to running Workbench 2

There is a solution to this problem, which entails disabling the CDTV functions. This will allow Kickstart 2.0 to work with the CDTV, at the expense of the CD-ROM drive. This does work in conjunction with a ROM switcher, though, so you could have Kickstart 1.3 and the CDTV functions intact, or you can switch to Kickstart 2.0, losing the CD-ROM drive.

To do this, open the CDTV up, and remove the jumper on JP15, which is near the front centre of the CDTV. Removing this jumper disables the CDTV functions, placing it on the left two or right two pins (it doesn't matter which) will enable the CDTV functions. You could put a SPST switch across the left two or right two pins, and use that in conjunction with your ROM switcher to turn off and on the CDTV functions at the appropriate time. Remove the Kickstart 1.3 ROM from socket U13, which is near the back centre of the CDTV. Place the Kickstart 1.3 ROM in your ROM switcher along with the 2.0 ROM, and put the ROM switcher back in the Kickstart socket U13.

To use Kickstart 1.3 and the CD-ROM drive, enable the CDTV functions by flipping the switch to on, then select the Kickstart 1.3 ROM on your switcher.

To use Kickstart 2.0, disable the CDTV functions by flipping the switch to off, then select the Kickstart 2.0 ROM on your switcher.

Of course, enabling or disabling the CDTV functions should be done with the CDTV power off.

Developer EPROMs

Commodore at one time did have a fixed set of CDTV EPROMs that worked with Workbench 2. These replace the EPROMs in sockets U34 and U35, and allow the use of a standard Kickstart 2.04/2.05 ROM in the CDTV. The bad news is that when they were available, they were only available to developers, and were included under the non-disclosure agreement. This essentially means that they were never available to the public, and that developers could not sell their ROMs to the public even if they are no longer using them. Being a CDTV developer for AmiTrix Development, I have a set of these EPROMs in my CDTV, which does work quite nicely under Workbench 2.1, although older CDTV products like Lemmings don't run because of Workbench 2. However, since these assets now belong to Amiga Technologies GmbH, without permission from them, it will be illegal to sell or otherwise distribute these, so don't ask me for them, please!

TOMS Kickstart 3 Adaptor

TOMS in Warsaw, Poland has devised some method of using Kickstart 3.x ROMs with the CDTV. Contact Rafel Wiosna
<> for more information.

W.A.W. Elektronik CD Bios *NEW*

W.A.W. Elektronik has two products to allow you to run Kickstart 2.x with your CDTV.

CD BIOS is a replacement for U34 and U35 which allows you to use a standard Kickstart 2.04 or up ROM on your CDTV. This option costs 65 DM.

CDTV OS2.x includes the CD BIOS above plus the Kickstart ROM if you don't have a spare Kickstart 2.04 ROM. This costs 100 DM.

They also have a Kickstart switcher, CD-Kick which allows you to switch between two ROMs. This is 40 DM.

Hardware Pinouts

* Memory Card Port

* Video Slot:

* Expansion Slot:

*Diagnostic Slot:

Hardware Hacks For the CDTV:

* CDTV Joystick Adaptor

Manufacturer Addresses: *NEW*

W.A.W Elecktronik GmbH

Acknowledgments: *NEW*

This information is based on the following sources and e-mail from the following people. Thanks!

* Rafel Wiosna <>

* Marc Biegota <>

* CDTV Service Manual

*Commodore Amiga A500/A2000 Technical Reference Manual

*Joystick/Mouse Adaptor for the CDTV

*CDTV Video Module Adaptor

*CDTV Zorro II Adaptor

*CDTV Meets 2000 Keyboard

Darren Ewaniuk,
Last updated July 5, 1997