MZ-700 Graphics

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mz-80a
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MZ-700 Graphics

Post by mz-80a » Mon Jan 20, 2020 1:26 pm

Hi,

Can I just get this cleared up : The MZ-700 doesn't have a second page of video RAM (like the 80A) does it? So you can't double buffer?

Thanks!
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hlide
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Re: MZ-700 Graphics

Post by hlide » Tue Jan 21, 2020 10:01 pm

No, MZ-80 A is the only MZ to allow a double buffer because of the video chips it has. While MZ-700 has two pages, the second page cannot be displayed : you need to swap or copy bytes between them which is very slow because both pages can only be accessed during the horizontal blanking (signal /WAIT is asserted negatively until HBLANK is 0 when trying to access VRAM).

Also that's one of the reasons MZ-700 is not technically retro-compatible to MZ-80 A and it said to be to MZ-80 K.

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Re: MZ-700 Graphics

Post by mz-80a » Wed Jan 22, 2020 11:04 am

Ok thanks. That's what I thought. It kind of makes the MZ-80A a bit more special!
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Re: MZ-700 Graphics

Post by hlide » Wed Jan 22, 2020 12:45 pm

It looks as if MZ-80A is the low-cost version of MZ-80B (professional target). For instance, the video chips and the expansion bus would be more in common with the MZ-80B than the MZ-80K. I see no successor to MZ-80A which was only for oversea (MZ-1200 for Japanese market). I remember I read an Japanese article discovering the MZ-80A and looking for adding color output. It was mentioned some similarities between MZ-80A and MZ-80B regarding hardware. Most hardware additions not specific to MZ-80K are not found in the MZ-700 and next generations.

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Re: MZ-700 Graphics

Post by mz-80a » Thu Jan 23, 2020 11:05 am

I don't think the MZ-80A and the MZ-1200 are similar. The MZ-1200 seems more like a K but in an A chassis
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hlide
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Re: MZ-700 Graphics

Post by hlide » Thu Jan 23, 2020 3:24 pm

Yes, probably the same way as between MZ-800 and MZ-1500 which the only common thing is the fact they are retro-compatible to MZ-700.

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Re: MZ-700 Graphics

Post by hlide » Thu Jan 23, 2020 3:28 pm

Details of differences between MZ-80A and MZ-1200: http://retropc.net/ohishi/museum/mz1200.htm.

In that article, you will find a lot of interesting detail about the hardware : a color screen was almost available for instance on MZ-80A.

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Re: MZ-700 Graphics

Post by mz-80a » Fri Jan 24, 2020 8:34 am

Pretty interesting!

On a tangent : Does anyone know what the naming scheme actually means for things like SA-1510 and SP-1002 ? What is 'SA' and what is 'SP' ?
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