Super turbo PCB layout

No need th shoot at a person that wants to give something back to the community. Let's see your PCB layout.

If you use a pull-up resistor (e.g. 4k7) for the IOB6 input it is still usable for someone to connect it to a free IO decoder pin in his or her MSX.

Wrt the GAL, is there only a JED file available or also the full sources? Checking the schematic I see datalines D6 and D7 are connected. I guess D7 is used for setting and reading the turbo status. Not sure what D6 is for.

Can we do 1 layout at a time, because 2 interleaving projects gets a bit complicated.

Agreed. The thread I've pointed up above has a lot of info related to this design...

As I can read in the threads I've pointed up:

RetroTechie dixit: "If that's fine the clock output will switch between X1 and X2 clock frequencies (keep schematic in mind for which is turbo frequency, and which is 3.58 MHz). Then you can hook it up to your MSX. Basically it takes the place of that red line you drew between VDP CPUCLK output & Z80 clock input (pin 6). So you'll have to cut that connection somewhere & 'inject' the turbo circuit's clock output there (and feed VDP's 3.58 MHz to X1 input of the turbo circuit). But check schematic to see how the CPU clock is routed, where it comes from & where it goes to (and check that on your mainboard, service manuals are often, but not always accurate). For one thing: it will also go to the MSX engine, and the engine will need the turbo'ed clock signal as well since it uses Z80 clock to time DRAM signals. If you connect a 3.58 MHz crystal between X1 points, you can leave that until you have everything fixed in place, and only then replace that crystal with VDP's 3.58 MHz signal."

I'm not very knowledgeable; but I understand that you need both clocks, using a crystal or feeding from VDP...