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3 votes

Are a Z80 address pins tristate?

I'd like to know if the address line go tristate when the CPU is neither reading or writing memory (or IO). No, they don't. At least not until the CPU is asked to release the bus - wihch is what /...
Raffzahn's user avatar
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3 votes

Are a Z80 address pins tristate?

Yes, the Z80 can tristate its address bus, but only as the result of arbitration via BUSREQ. And there certainly were DMA controllers, both for the Z80 specifically, and generic ones that predated it. ...
Dave Tweed's user avatar
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3 votes

DIY Project using 1970s 8-bit CPU, is it possible?

The starting point is why you want do do this, and what you will do with it. If you're eventually doing to add floppies and use it, probably the z80, for the CP/M software. The 6502 has some serious ...
hawk's user avatar
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0 votes

Did any Apple II games use a "timing resistor"?

Using that method for timing would seem unlikely, as the ][ used a cpu loop to read the paddle value--so it wasn't doing anything else while reading. However, you conceivably count on your estimate of ...
hawk's user avatar
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3 votes

Were there 3D accelerators built on discrete logic?

Although not exactly "3d" by modern standards, the arcade machine Star Ship from the 1970s used hardware scaling to allow an enemy ship sprite to grow in size as it got "closer". ...
supercat's user avatar
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22 votes

Were there 3D accelerators built on discrete logic?

Since you list texturing in the hard requirements for a 3D accelerator, the earliest instance of a 3D accelerator could have happened only 1974 or later – the idea of algorithmic texture mapping comes ...
Marcus Müller's user avatar
3 votes

Were there 3D accelerators built on discrete logic?

This sounds quite hypothetical, more important seems to miss the timeline, as 3D accelerators only became a thing to create when large scale real time 3D display solutions, needing such, became a ...
Raffzahn's user avatar
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13 votes

Were there 3D accelerators built on discrete logic?

3D accelerators in the sense you are describing for a pipeline rendering triangles etc. only came up after discrete logic was already phased out for much higher integration. So you'd have accelerators ...
dirkt's user avatar
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