R.Cade Posted December 30, 2019 Share Posted December 30, 2019 (edited) I recently rebuilt my old 800XL thanks to a kind soul here on AtariAge that was giving away a broken board. Between the two I was able to make a working one. While I was in there, I did the video upgrade to add Chroma out, changed to Hias' Hi-speed SIO patched ROM, snipped the SIO caps on the data lines, and put in the 4k7 resistor betwen DATAOUT and 5v. To my surprise, my very old SDRIVE works in divisor 0 on this 800XL! It's very strange since I thought that the particular SDRIVE I have only works at a minimum of divisor 2, and that's the fastest it has ever gone in my 600XL. I made sure my 600XL has the same SIO mods- it does (C89 and C90 snipped, and the 4k7 is in place). However, the weird thing is- the 600XL works in divisor 0 fine with RespQt and a PC, just not with the sdrive. Is there something else different about SIO and the 600XL vs. the 800XL? Edited December 30, 2019 by R.Cade Quote Link to comment Share on other sites More sharing options...
JR> Posted December 30, 2019 Share Posted December 30, 2019 My SDrive-MAX works fine at DIV 0 in my 600xl with just the caps snipped. Quote Link to comment Share on other sites More sharing options...
Faicuai Posted December 30, 2019 Share Posted December 30, 2019 Here, for SDrive NUXX running @ Divisor-0 (800XL) and Divisor-1 (800/Incognito), all day long, with ZERO mods of any kind: Quote Link to comment Share on other sites More sharing options...
777ismyname Posted December 30, 2019 Share Posted December 30, 2019 I finally got to experience POKEY divisor 0 recently...and I liked it lmao ? Seriously , it does rock. 1 Quote Link to comment Share on other sites More sharing options...
a8isa1 Posted December 30, 2019 Share Posted December 30, 2019 (edited) 10 hours ago, R.Cade said: I recently rebuilt my old 800XL thanks to a kind soul here on AtariAge that was giving away a broken board. Between the two I was able to make a working one. While I was in there, I did the video upgrade to add Chroma out, changed to Hias' Hi-speed SIO patched ROM, snipped the SIO caps on the data lines, and put in the 4k7 resistor betwen DATAOUT and 5v. To my surprise, my very old SDRIVE works in divisor 0 on this 800XL! It's very strange since I thought that the particular SDRIVE I have only works at a minimum of divisor 2, and that's the fastest it has ever gone in my 600XL. I made sure my 600XL has the same SIO mods- it does (C89 and C90 snipped, and the 4k7 is in place). However, the weird thing is- the 600XL works in divisor 0 fine with RespQt and a PC, just not with the sdrive. Is there something else different about SIO and the 600XL vs. the 800XL? Classic SDrive only worked with divisor 3 and lower if Hias Reichl's firmware is installed. That firmware had been available as early as 2009 IIRC. Paired with Hias' MyPicoDOS S0 the two items together work great. No OS mod or patch needed to load games at 128kbits even on good old 800. With MyPicoDOSS0 you don't need to use the SDrive configuration program to set the speed. MyPicoDOS does the setting for you to run with divisor 0. (There's also MyPicoDOS S1 which uses divisor 1). Come to think of it. Hias' XL/XE OS HISIO ROM patch works at divisor 0 as well (and not just with SDrive). so it's WIN WIN WIN! Three wins! Thanks Hias! Edited December 30, 2019 by a8isa1 1 Quote Link to comment Share on other sites More sharing options...
R.Cade Posted December 30, 2019 Author Share Posted December 30, 2019 (edited) I double checked- I snipped the right capacitors on the 600XL (two of them actually), traced back to the pins 3 & 5, which is C89 and C90. I measured the resistance on the 800XL between pin 5 and pin 10 with the 4.7k resistor, and it was 2.6k or so. The 600XL had only 2.3k, so I added another 1k in series to bring it up to match the 800XL, but I don't think it's that sensitive- this is just a pullup. No difference, and I'm not sure the 4.7k on DATAOUT affects the speed anyway? The 800XL with the same OS ROM (Hias) works with this SDrive at divisor 0, no errors ever. The 600XL will not work past 2. Both work with divisor 0 on a SIO2USB. I have to just shrug at this one. Edited December 30, 2019 by R.Cade Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 24, 2021 Share Posted January 24, 2021 Perhaps your 600XL has a problem pokey, pia, or timing support chip... even a or incomplete, possibly noisy cap issue. While you sort it out you might check if the 600XL has a memory upgrade on the main PCB, if not, nows the time to do it. Quote Link to comment Share on other sites More sharing options...
R.Cade Posted January 24, 2021 Author Share Posted January 24, 2021 Oh yes... post from a long time ago. Both my 600XL's have the RAM upgrade. Both have this issue that's not really an issue. The SDrive NUXX I have should not work at divisor 0 without the newer firmware, which I don't have. It's just some kind of fluke that it works with the 800XL. Quote Link to comment Share on other sites More sharing options...
BillC Posted January 25, 2021 Share Posted January 25, 2021 On 12/30/2019 at 2:11 PM, R.Cade said: I double checked- I snipped the right capacitors on the 600XL (two of them actually), traced back to the pins 3 & 5, which is C89 and C90. There is also a capacitor on COMMAND, C75/SIO pin 7, I don't know whether this would affect high-speed operation. Quote Link to comment Share on other sites More sharing options...
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