Posted By
Luca
on 2014-11-08
07:09:22
 |  Re: Converting SID tunes to the Plus/4
$D400 -> $FD40
We used to keep up with the Csory's SIDcard and its $FE80 SID addressing just because traditionally the most spread SIDcard (The Solder's one) has been built up to be compatible to the earlier Csory's one, and the new from NST follows the trend. If you look at our Hardware page, we still don't know how the heck is done that $FE80-driven stuff  Marq splittedThe First Ball Plus/4 in two different versions, one for $FD40 and one for $FE80 and I still don't know why (I told him he only would have needed the first one but he followed another way...).
Autodetecting SIDcard should be easy, as booting a Plus/4 with SIDcard on entails to have all zeroes in the $FD40-$FD5F/$FE80-$FE9F areas with the value $FF into $FD59 $FD5A $FE99 $FE9A, memory areas usually filled with their respective hibytes once booted up the machine (#$FD/#$FE). Uselessly deeper, NST's SIDcard has its own flag to achieve this, and there's a little example in the manual (get it online) about how to detect if the card is a Solder's one or not.
And about the frequencies question: yes. I myself used in the past to compose a tune for one machine and then apply some changes in the slide/glide stuff in order to fix it for the other one. Of course there is also a global shifting in the notes while playing a tune on its non-native iron...but I'll leave all this to TLC, which is the real expert here 
What I can suggest is to read all the text TLC did write for SIDwinder V01.23, I've copied and put straight on its page just for this kind of needings. Most of all, read the Specific Plus/4 Notes!
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