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Re: TFMSX Arrives
Posted: Thu Apr 08, 2021 7:47 pm
by Steve
Wow! nice work, I don't know much about the MSX except there are a few different generations/versions - where does your home-made one fit compared to the others spec wise?
Re: TFMSX Arrives
Posted: Thu Apr 08, 2021 10:18 pm
by terriblefire
First issue with the TFMSX. I was trying to clock the Z80 with a 3.3v clock. It appears to need a VCC-0.6v minimum for high on the clock lines. Everything else is much less picky so i found a 74LVC1G17 chip and patched it on there.
Seems much happier now as i see RD wiggle furiously.
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Re: TFMSX Arrives
Posted: Thu Apr 08, 2021 10:22 pm
by exxos
exxos approves the bodge wires
Re: TFMSX Arrives
Posted: Fri Apr 09, 2021 2:27 pm
by Cheshire Noir
terriblefire wrote: ↑Thu Apr 08, 2021 2:13 pm
Well right now its a pet project.
Indeed, and a worthy pet project too. I'm just enjoying watching it get built. Somewhere down the track, if/when you release them to the usual suspects (And I have no expectations that this will happen, and want no part in applying any pressure for this to be anything more than a fun pet project for you) I'll probably see if I can purchase one. Not this year, however, as I am buying peripherals for all the systems I already own. So... many... shiny... systems!
Chesh
Re: TFMSX Arrives
Posted: Fri Apr 16, 2021 7:44 pm
by terriblefire
It’s alive!!!
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Ok so this wasnt so straightforward. Adding the Schmitt buffer made the clock line ring like a church bell. and it didnt run at 3.58Mhz.
So now i need to make another one for
@arkadiusz.makarenko so he can do the keyboard.
Re: TFMSX Arrives
Posted: Fri Apr 16, 2021 8:12 pm
by b_squared
Great work, I'm excited to see what will come of this! MSX user since 1990 here. Two questions:
- Which BIOS are you using here?
- How are you handling cycles to the VDP for the turbo modes? Did you hook up the /WAIT signal?
Re: TFMSX Arrives
Posted: Fri Apr 16, 2021 8:22 pm
by terriblefire
I'm presently using the Bios from a HX-10.. keeping at simple as possible.
I've no turbo modes setup yet. but when i do i'll change CPU speed for different accesses so that VDP will always be at 3.58Mhz..
If anyone is interested the board uses 600mA @5V idling at a basic prompt.
Re: TFMSX Arrives
Posted: Sat Apr 17, 2021 9:25 am
by arkadiusz.makarenko
:O
That was quick.
Re: TFMSX Arrives
Posted: Sat Apr 17, 2021 10:22 am
by terriblefire
Yeah i need some help now!
USB keyboard!!!!
Here is how the keyboard matrix map looks...
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PC0-3 are connected to the ARM like...
Code: Select all
PC0 = ARM PIN8
PC1 = ARM PIN9
PC2 = ARM PIN10
PC3 = ARM PIN11
and the return signal to the MSX
Code: Select all
PB0 = ARM PIN 14
PB1 = ARM PIN 15
PB2 = ARM PIN 16
PB3 = ARM PIN 17
PB4 = ARM PIN 20
PB5 = ARM PIN 21
PB6 = ARM PIN 22
PB7 = ARM PIN 23
I'll build you a board if i have time otherwise i'll ship you the number 1 prototype.
Re: TFMSX Arrives
Posted: Sat Apr 17, 2021 10:35 am
by arkadiusz.makarenko
I can find time for this...
