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  1. That would be super cool! I know the original data sheet listed 4MHz versions I was never able to find them or see them - maybe they all ended up in some old cruise missile? The best would be to have the socket on the M/B but I understand that ship has sailed, and besides there is only so much space on a tight board. But I think the critical part here is the software - X16 is still very much a Microsoft Basic computer, so to really utilize it (beyond Mandelbrot demos) is to have a version which replaces all "software FPU" routines with calls to Am9511. The storage of floating point variables in memory probably should still be 5-byte format (if I am not mistaken), so quite a bit of conversion. Or go for deep change and really use 4 bytes and save some memory. Or 4-bytes but real IEEE754 format - lots of dilemmas! Either way, the boost in Basic would be significant as lots of variables are by default FP. Btw, the code I shared could be used for simple test as it runs through lots of calculations. I generate the clock for Am9511 in software on the Propeller, so it is easy to test the upper limit. I have dismantled my test rig, but it could be replicated essentially with just a few wires on this board: https://www.parallax.com/product/propeller-activity-board-wx/ - the breadboard is already there. One just needs a 5V to 12V boost up voltage converter, or maybe not even that if the supply voltage is stable 12V because from what I see some pins make it available. The Propeller flip-chip will work too (cheaper!) but then you have to supply own breadboard.
  2. Hi, If I understand correctly, the motherboard will have ATX power supply compatible connector? If so, will some (all?) of these voltages be present on expansion slots? Having +12V is super useful for old EPROM programmers and such, +/- 12V for old RS232 etc. Also some really ancient chips use +/- 5V, +/-12V - for example imagine a 8080 test board (oh, the sacrilege!!!). What I am thinking mainly is Am9511 which takes +12V and +5V, combined with 32 reserved I/O locations would be perfect fit for an expansion board.
  3. The perfect "retro" style solution to the FPU problem is using Am9511 - these are still quite abundant, interfacing is easy, and offer 10X speed up of all FP operations. Most run at 2MHz so some bus wait cycles would have to be included. Too bad the motherboard does not have an open socket for them but I am sure they could be added later on expansion card, and with Basic modified to use them it would be great speed boost. https://github.com/zpekic/am9511
  4. Hi all, Love this project and the ideas behind it! I think it is more than just nostalgia, it is a need bring back full understanding and mastering over the technology, something that slipped away over the decades of exponentially growing complexity. There is beauty in achieving and building something from limited means too. Some retro-computing related projects here: https://hackaday.io/projects/hacker/233652 Various code attempts: https://github.com/zpekic?tab=repositories Few demos: https://www.youtube.com/channel/UCLBfVhnIwKCVX5VPAezAeWQ Looking forward to learn a lot, and maybe to contribute a bit too. Happy computing to all! Z.
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