V9958 on an MTX

Modern, Memotech inspired, hardware projects
Martin A
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V9958 on an MTX

Post by Martin A » 21 Sep 2014 23:05

after tweaking.jpg
Output from the V9958
after tweaking.jpg (93.99 KiB) Viewed 2873 times
Testing on the EB512.jpg
MTX512 driving a V9958 video processor
Testing on the EB512.jpg (161.76 KiB) Viewed 2873 times
Minor success today, first output from the V9958 supplied by Lez, being driven by the much abused MTX500 I upgraded to 64k.

That's half the amount that's on the video board, and there are 2 sockets obscured by the daughterboard that could bump the video ram to 192k.

The visible empty socket is designed to take a sound chip, but that has yet to be tested.

lezanderson
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Re: V9958 on an MTX

Post by lezanderson » 21 Sep 2014 23:53

AWESOME !!

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Dave
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Re: V9958 on an MTX

Post by Dave » 22 Sep 2014 00:28

Well done !

That looks like a really good design, wherever did you find it?

:-)

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1024MAK
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Re: V9958 on an MTX

Post by 1024MAK » 22 Sep 2014 00:42

I think the answer to Dave's question is: down the back of a sofa?

Well done Martin.

Now does this mean we get a colour version of textinvaders?

Mark

Martin A
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Re: V9958 on an MTX

Post by Martin A » 22 Sep 2014 19:52

1024MAK wrote: Now does this mean we get a colour version of textinvaders?

Mark
Hm I guess that depends on the market, what's your estimate of the number MTX's there are out there running with a V9958 expansion? :D


I was cheating a little to get the display set up, the 9958 was set to respond to ports 1 and 2, effectively shadowing the on-board VDP (which is driving the mono screen). However it does also demonstrate the backward compatibility Yamaha built in.

It does work using it's "normal" ports, but takes a lot of OUT 152 and 153's just to print "Ready" in text mode, getting a display complex enough to "tune" in the picture would have taken quite a while.

Martin A
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Re: V9958 on an MTX

Post by Martin A » 26 Sep 2014 15:51

G7 Test-sm.jpg
Graphics mode 7
G7 Test-sm.jpg (88.24 KiB) Viewed 2839 times
Graphics mode 7 tested

It's a bitmapped 256 x 192 mode in 256 colours

I'm still running composite video output.

The very basic BASIC used to set up the display can be seen on the other screen.

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1024MAK
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Re: V9958 on an MTX

Post by 1024MAK » 28 Sep 2014 11:47

Nice :D

Keep them updates coming :P

Mark

Martin A
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Re: V9958 on an MTX

Post by Martin A » 30 Sep 2014 20:16

Nothing new from the weekend, I got side-tracked putting together some 6309 based hardware.

I WILL get the 80 column text mode tested, I promise!

Martin A
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Re: V9958 on an MTX

Post by Martin A » 05 Oct 2014 11:23

Just for Claus:

Have a look at E
menu option.jpg
Magrom gets a new option
menu option.jpg (136.94 KiB) Viewed 2793 times
I was experimenting with Graphic mode 7: I wanted to show something a litle more interesting that a colour chart.

As I'm using Magrom to load the image, I've had to keep within the 28k or so file size that the board limits me too.

The original image is 192 x 139 8 at 8 bits per pixel its just over 26k in size leaving enough room for the code.

It's scaled up to 192 x 208 to restore the aspect ratio.

A better "delivery system" would have allowed a full screen image, with a little more detail.

Still, it's not a bad indicator of the possibilities

It may be possible to rival the HRX?
output.jpg
Surprise!
output.jpg (84.96 KiB) Viewed 2793 times

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Dave
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Re: V9958 on an MTX

Post by Dave » 05 Oct 2014 12:03

So, what would you little maniacs like to do first?


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