The Taka-Nami board replaces the Z-80 CPU in a MSX/MSX2 computer with a modern Z-80 (Z84C) which runs cool at 20 MHz without altering the system clock for the rest of the board.
That way, a high level of compatibility with classic software is achieved.
Requirements
- Any MSX with a socketed Z-80. If yours is directly soldered to the PCB, you need it to be removed and a socket installed. That’s the only mod you need to do. No wires needed.
- Enough clearance in your MSX model pcb to fit the Taka-Nami. Check orientation and location of the Z-80 in your system board. More details can be found later and possible solutions.
In addition to the system boost, Taka-Nami provides a large 512 KB of fast RAM that replaces your system ram. More than enough to run most MSX software.
Installation
Provided that your system board has a socket for the Z-80, simply remove the Z-80 and insert the Taka-Nami. Check the orientation of the Taka-Nami matches the notch on the socket (the orientation of the original Z-80)
The board is very low profile to avoid hitting the case or the keyboard of your MSX, but sometimes it is so low that it can hit other chips or components aside, where the board extends from the socket. In that case, it can come handy to bring up the Taka-Nami interposing one or two DIP40 sockets (better use the ones with round “machined” pins to match the pins in the Taka-Nami).
The “turbo enable” jumper can be left on because the MSX should boot perfectly at 20 MHz, but It can be routed to a mechanical switch too if you want to control the turbo anytime from the outside of the computer.
Before you can proceed to config the board using the jumpers. You need to know your computer slot map to see where the system RAM is located. A very good source of this information is msx.org, if you don’t know it already
Configuration
You need to set the jumpers in order to get Taka-Nami to replace the correct slot/sub-slot and place there the fast ram in your machine.
To see the exact jumper locations and configurations, see the manual (link)
- If your MSX places all the memory in a primary slot (can be slot 1, 2, or 3, common for MSX computers) use a regular slot substitution in that slot.
- If your MSX places the ram in and expanded slot 0, you should be able to boot, and use a special tool to enable de ram afterwards. Note that this feature is under development.
- If your MSX places the system RAM in a sub-slot in slot 3, choose one of the expanded slot 3 options, specifying the sub-slot for replacement.
Once you have the slot configuration done, you’re already ready to boot. You should see the normal boot to basic or firmware in your MSX.
Using the turbo
The turbo speeds can be configured using the keyboard (with limitations, see manual) or via software control.
Pressing CTRL+GRAPH anytime, the speed will cycle to next higher speed up to 20 MHz and then, to 3.57 MHz (no turbo) again:
-> 3.57 MHz -> 6 MHz -> 10 MHz -> 20 MHz -> 3.57 MHz …
NOTE: turbo speeds lower than 20 MHz are simulated with wait-states, the CPU runs either at 3.57 MHz or at 20 MHz, always.
The speed change comes handy if your storage cartridge can’t work with turbo speeds. You can use the keyboard to load whatever you need at a lower speed, and then pump up the speed afterwards.
More features
More features are under development to further increase performance with bios, and more. Note that this feature is under development.
Installation issues and recommendations
If your Z-80 location makes the Taka-Nami collide with something in your MSX board and that prevents the installation, you can inter-impose a relocator between the Taka-Nami and the system board. We are providing some for selected MSX models, and some others in the community have done it before too.
If your system board has the Z-80 CPU directly soldered and you want to remove it to put a socket in its place, consider asking someone that has the needed knowledge to do it safely and ask him to use a high quality socket. A round “machined” pins one is recommended because it better matches the Taka-Nami round pins.
Have a nice time with your turbo MSX!