TFMSX Arrives

[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?

[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.

WhatsApp Image 2021-04-08 at 22.13.22.jpeg

[exxos]

exxos approves the bodge wires :lol: :thumbup:

[Cheshire Noir]

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

[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.

[b_squared]

Great work, I'm excited to see what will come of this! MSX user since 1990 here. Two questions:

1. Which BIOS are you using here?
2. How are you handling cycles to the VDP for the turbo modes? Did you hook up the /WAIT signal?

[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.

[arkadiusz.makarenko]

:O
That was quick.

[terriblefire]

:O
That was quick.

Yeah i need some help now! :D USB keyboard!!!!

Here is how the keyboard matrix map looks...

matrix.PNG

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.

[arkadiusz.makarenko]

I can find time for this... :)