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Frantic
Registered: Mar 2003 Posts: 1661 |
Configurable addresses in multi sid tunes please
Hi guys!
If you want to make a fellow scener a tiny bit happier than he already is:
In multi sid tunes (2 sid chips or more) it would be super nice if more people started to add the possibility to configure the adress of the extra sid chips before the tune starts playing. After all, if you play multi sid tunes on a real machine it may not be easy to change the addressing of the extra sids you have. Sometimes there are jumpers which allow a bit of configuration (such as switching between de00 and df00, or between d4xx/d5xx or something). However, in many cases the configuration options are limited. For example, in my 3sid-machine, the sid chips are located at $d400, $d420 and $d500 and that's that. I can't change it. No jumpers or stuff like that. :)
I understand that most people use VICE or various cross platform music editors, or emulated+configurable "sid chips" like the ones in the 1541U2, when they deal with multi sid stuff, but still.. the real machine with real hardware sid chips is always the main target, right? ;)
Thanks in advance! ;) |
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chatGPZ
Registered: Dec 2001 Posts: 11523 |
that would require a whole lot of logic to decode and generate the chip select etc. could be a fun project to build for some TTL fetishist =) |
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Krill
Registered: Apr 2002 Posts: 3098 |
Quoting Groepazthat would require a whole lot of logic to decode and generate the chip select etc. could be a fun project to build for some TTL fetishist =) I thought that "configurable register layout" would already suggest using a CPLD or so. Discrete logic for that would be pretty hardcore indeed. =D
And then this isn't limited to discrete (or even physical) SIDs either. =) |
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chatGPZ
Registered: Dec 2001 Posts: 11523 |
not sure what you mean with "configurable" ... like, having an option to change the mapping via some extra registers? that would then require a helluva lots more logic too - cpld (or fpga) or not :) |
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Krill
Registered: Apr 2002 Posts: 3098 |
Quoting Groepaznot sure what you mean with "configurable" ... like, having an option to change the mapping via some extra registers? that would then require a helluva lots more logic too - cpld (or fpga) or not :) Yes, that. Doesn't seem more complex than other designs for C-64 add-ons implemented via CPLD/FPGA, though. =) (The actual logic, that is. Routing physical lines etc... different problem. =D) |
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tlr
Registered: Sep 2003 Posts: 1814 |
Quote: that would require a whole lot of logic to decode and generate the chip select etc. could be a fun project to build for some TTL fetishist =)
Not too difficult. Let the address bus of the SIDs be connected to A5-A9 instead of A0-A4, then generate the chip selects using a TTL decoder. Use for example four 74LS138s (1 of 8) or two 74LS154s (1 of 16).
Configurable, much trickier. :) |
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Krill
Registered: Apr 2002 Posts: 3098 |
Ok, but i was mostly aiming at feasibility of the layout when addressing registers via software, in a multi-SID player routine.
Also what about grouping in a voice-oriented way, such that there would be no offset of 7 between closely related registers for each of the 3 voices of a single SID, but an offset of 1 for all 3*N addressable voices. =D |
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chatGPZ
Registered: Dec 2001 Posts: 11523 |
Those are good ideas.... for 1982 =) |
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tlr
Registered: Sep 2003 Posts: 1814 |
If you'd settle for 8 SIDs max, each of the four pages $d400-$d7ff could have a mirror of all 8 SIDs in 4 different layouts. |
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Frantic
Registered: Mar 2003 Posts: 1661 |
In relation to the nice 3sid and 2sid releases at Xenium 2021 I just want to point out that it would be super cool to be able to play them on real hardware, which for some (me included, obviously) requires the possibility to configure the addresses (in my case to $d400, $d420 and $d500).
All of the tunes from Xenium 2021 used $d400, $d420, $d440.
Now, of course I don't expect anyone to do extra work just because I am sitting here wishing that I could play these 3sid tunes on my machine, but I still throw this out in case it would turn out to be trivial for the authors to achieve this configurability and in case it would allow more people to enjoy 3sid tunes on the real machine with real SID chips. |
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Jammer
Registered: Nov 2002 Posts: 1343 |
Gotta implement it one day in MSL wrapper but seems like tough bitch to figure out in order to handle every single routine. |
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