Expanding the Sequential TOM to hold 16 "cartridges"
I bought my TOM a few years ago, and had always intended to make some sort of switch-able cartridge for it. I decided recently that it would be nicer to have everything inside the TOM, if possible, and control it using the TOM user interface. There are two advantages to doing it this way:
1) Cartridges can be selected without unplugging and replacing EPROMs, which can get damaged by ESD or bent pins.
2) Both the internal sounds and the cartridge can be swapped out, so all 15 sounds can be changed, not just the top 7. There are two "slots" - internal and cartridge. Any of the 16 "cartridges" can be placed in either slot. If a cartridge has seven sounds in it, and is placed in the internal slot, button 8 will not make a sound. All of the cartridges I have made have 8 sounds. If they are placed in the internal slot, all 8 are available. If they are placed in the cartridge slot, only the first 7 sounds are available.
The board plugs into one of the internal sound ROM IC sockets, after both chips have been removed. It also needs A15b and A16b which are not available in either socket, so two short wires are used. I use A15b and A16b instead of A15 and A16 to avoid connecting to the Wonder chip signals. Luckily there are eyelets on the TOM board right where I needed them to be for these two signals.
Here is a photo showing the prototype installed in my TOM:
And here is a photo showing the original version of the pcb, with the two small yellow wires in place:
Here is a photo showing the newer version of the pcb, which has a third wire. The original two wires are connected exactly as before, while the third wire attaches to the lower end of the 10K resistor near the battery. I have added a small circuit which should allow inserting a cartridge (for testing) into the TOM while the TOM16 is installed. In this case, the only sounds available would be the ones on the cartridge, as the TOM16 EPROM is disabled.
How does it work? I added code to the TOM V1.6 OS firmware (the final SCI version) to allow selecting cartridges using the std user interface. Once the selection is made, these values are sent using the Wonder chip in a special way to a PIC micro-controller on my board. That chip presents the two cartridge select 4-bit codes to a dual 4:1 mux that feeds the correct one to an 8 Mbit EPROM. I do not plan to release the PIC code, or provide the source for my version of the TOM OS at this time. The only changes that I made to the TOM OS firmware were for TOM16 support. No other changes were made.
I am currently offering fully assembled pcb's for $100 including Priority Mail shipping to USA addresses. If you are outside of the USA, please contact me for the additional shipping cost. In order to install the board in your TOM, you will need to upgrade the (socketed) firmware EPROM with one that I supply. You will also need to remove the two (socketed) sound ROM chips I610 and I611. And finally you will need to carefully solder three wires, (which I will supply) into small holes in the TOM pc board and in my board.
Here is a schematic diagram of my design.
Here are instructions for installing the TOM16 pc board.
I included the original Sequential internal sound EPROMs as cartridge index 0, plus the four Sequential cartridges. To these I have added six "Drumware" cartridges. That left five open positions. I have filled these with one TR606, two CR78, one TR909, and one TR808 cartridge (designed to complement the Drumware 808 cartridge).
Here is a list of the sounds included in the TOM16, grouped as cartridges numbered 0-15, any two of which can be selected at a time.
Here is the same list as a text file.
Here is an archive containing all sixteen binary cartridge images used, a binary image of the 8Mbit EPROM, and an image of the V1.6 firmware EPROM.
Note: Once the V1.0 TOM16 pcb is installed, the TOM cartridge slot is no longer usable, and nothing should be plugged into that slot, as it would conflict with the internal EPROM and neither one would work. If you have the V1.1 pcb, it should be OK to plug in a cartridge, but the TOM16 sounds will be disabled.
Drumware Cartridges for the TOM
Back in the day, a company was offering additional cartridges for the TOM beyond what Sequential was offering. They were called "Drumware". Someone was nice enough to loan me his cartridges so that I could use them in my TOM16cart project, so I am also making the EPROM binary images available here, in case anyone wants to program their own cartridge with them. I have included wave files for each, so you can listen to them easily. There are six cartridges: Rock Drums, Techno Drums, Orchestral, Hippefex 1, Analog Drums (TR808) and Percussion 3 (Latin drum sounds). I scanned the labels, which listed the sounds, and have included the result. I did not have a label for Rock Drums. All of these sounds are included in my TOM16cart.
Copyright © 2007-2016 by TaunTek.com. All rights reserved.