Super turbo PCB layout

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By Pentarou

Champion (351)

Pentarou's picture

29-04-2021, 17:42

SkalTura wrote:

So the GAL version cannot be used then.

Do you actually understand how the circuit works???

You just need to disable the software switching by connecting that pin to H.

By Gregory

Master (130)

Gregory's picture

30-04-2021, 03:28

Pentarou wrote:
SkalTura wrote:

So the GAL version cannot be used then.

Do you actually understand how the circuit works???

You just need to disable the software switching by connecting that pin to H.

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

By SkalTura

Champion (315)

SkalTura's picture

30-04-2021, 08:01

Pentarou wrote:

Do you actually understand how the circuit works???

No need to get agree dude, just want to help...
And the answer is: No Wink
I understand how the circuit should work, but not what all the inputs are suppose to do...

So if we connect the IOB6 input to (by "H" you mean "high" I suppose?) the 5V, then we don't have to do any other changes to the GAL circuit, and can be used together with the QFP Z80 ?
Just use the GAL circuit in the previous post and that's it...?

By lintweaker

Champion (395)

lintweaker's picture

30-04-2021, 08:39

SkalTura wrote:

So if we connect the IOB6 input to (by "H" you mean "high" I suppose?) the 5V, then we don't have to do any other changes to the GAL circuit, and can be used together with the QFP Z80 ?
Just use the GAL circuit in the previous post and that's it...?

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.

By jltursan

Prophet (2479)

jltursan's picture

30-04-2021, 09:16

The CIEL Turbo seems to have only jed files, posted some pages ago, can't see any sources.

Not specifically talking about the CIEL Turbo; but this thread is a good reading :)

By Gregory

Master (130)

Gregory's picture

30-04-2021, 09:09

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

By Gregory

Master (130)

Gregory's picture

30-04-2021, 09:11

SkalTura wrote:
Pentarou wrote:

Do you actually understand how the circuit works???

No need to get agree dude, just want to help...
And the answer is: No Wink
I understand how the circuit should work, but not what all the inputs are suppose to do...

So if we connect the IOB6 input to (by "H" you mean "high" I suppose?) the 5V, then we don't have to do any other changes to the GAL circuit, and can be used together with the QFP Z80 ?
Just use the GAL circuit in the previous post and that's it...?

I'd like to see you finfish the 74HC type first. That was kinda the starting point of this thread.

By jltursan

Prophet (2479)

jltursan's picture

30-04-2021, 09:23

Quote:

I'd like to see you finfish the 74HC type first. That was kinda the starting point of this thread.

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

By SkalTura

Champion (315)

SkalTura's picture

30-04-2021, 10:55

Gregory wrote:

I'd like to see you finfish the 74HC type first.

Not finished yet...
Only made the QFP to DIL40 adapter so far.

I tested the 74HC version in simulation software, but it seems to still need both clocks to work (at least for the simulation).
Of are you suppose to connect the "slow" input to the MSX clock by wire ?

By jltursan

Prophet (2479)

jltursan's picture

30-04-2021, 11:32

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...

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