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ATR8000 and UltraSpeed?


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Just curious -- I have normally used a PERCOM dual drive with single and double 5.25 and 3.5 drives in my brief encounters with the ATR8000. Through the PERCOM, there is no way to do US (that I've found). If a drive is hooked directly to the ATR8000, is US possible? I'm inclined to say "no," but I'm not sure. Anybody tried this before? I've looked briefly through the ATR8000 docs, and find nothing about US. Not surprising since the ATR was produced long before US/Warp Speed came about.



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I'm still interested if anyone has been successful with this, but I set up my ATR8000 with ISA drives, and there is sure no way that I've found to make US work. Pretty sure it is a "NO."


Edit: With a bit of experimentation, I found that if I hook a high-speed drive (in this case a US Doubler Rana), the high speed works great. So even if a direct connect does not allow high speed, one can still have high speed with the ATR8000 using SIO drives.



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IIRC, the Percom drives have a UART that is set at a fixed 19200 baud, and can't be (easily) changed. As I wrote in another post, the ATR-8000 is a bit-banger, which means that any speed is possible (within the timing limits of the Z80). The Indus GT does high speed very well with the code that is downloaded to it from SDX.


It should be possible to use a modification of the SDX code to burn a new EPROM for the ATR-8000 that supports high speed SIO. The code could be rewritten so half of the RAM is used for track buffer, and the other half used for print buffer.


Over the years, I have sadly forgotten much of my Z80 skills. Hopefully, someone can do this. I believe it would be a fairly easy project to create a new highspeed Indus compatible or UltraSpeed compatible EPROM for the ATR-8000.


There is a difference in how Hi and Ultra work. Ultra queries the drive for the PoKey divisor byte (the speed index), then sets up SIO for that speed. Hi sends a command frame with bit 7 set, and expects the data frame to be at the faster speed (IF I REMEMBER CORRECTLY).


I'm sure there is good information available online about this. Possibly ask Hias. He should know about this.


If someone figures this out, I may need to find another ATR-8000 (and put a GIDE hard disk interface in it) :)

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The ATR8000 can have programs up loaded to it. I personally have done it to create CPM system tracks. On boot up,the rom is copied to ram so any changes should be easy. Be very careful changing the rom. you may break CPM.

While at it, change the drive def blocks to allow 1.4 meg disk format. I believe the FDC can handle high density as it can be clocked at 1 or 2 MHZ. Am sure i will be corrected if i am wrong.



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