SwinSID - a pin compatible alternative to the SID chip

MIDIbox SID
1

Hi everyone!

I couldn’t hesitate to post this, as the search function didn’t throw any result.

It has been posted in misc section but I think it would be more significative to post it here.

To the point:

If you can’t find a SID chip (my case where I live), or you don’t want to cannibalize a C64, here’s an alternative: as it works in a real C64, I’m pretty sure it can work in a midibox but don’t know how good. I think it could be a great idea to give it a try, its better than nothing, you can also put a real sid in a midibox once you find one but in the meanwhile use a SwinSID.

Judging by the sound, I think I could give it a try:

http://www.swinkels.tvtom.pl/swinsid/

The project consists on a board featuring a “PIC” (or sort of), the ATMEGA8515 (15€ aprox, and its programer could be an appollo I2C, for 21€), The board is SID pin compatible, meaning you insert the board into its socket somehow… or via a bunch of cables. The thing simulates the whole SID chip.

This question would be to the midibox sid designer, maybe the SwinSID isn’t perfect, that could mean the midibox could crash or not work at all?

2

Hi,

first of all, I don´t think it makes much sense to discuss this project in two threads at the same time. Link to the original thread: http://www.midibox.org/forum/index.php?topic=9338.0

I think the SwinSID is a funny idea but doesn´t make much sense with a MBSID. After all, it is just a digital simulation of a SID. There are a several Windows-based SID simulations/SID players, and people are here because they want to have the real thing and not another emulation.

And to build one is some financial and work effort. You need to find all components for a reasonable price (15 Eur for an ATMega8515 is outrageus, the normal price is around 3 Eur!), build it, find out how to program an Atmel etc. And when you´re finished you´ve got only something that sounds only “quite like” a SID. A lot of work - “quite like” you can also get with only software.

Is there no way for you to buy a C64 internationally via eBay? even if it costs 30 Eur shipping, it would still be not much more expensive than building a SwinSID.

If it would work? Possibly yes. At least the midibox won´t crash because of it because the connection from the core to the SID is one-way. So the core will be fine regardless of what the SwinSID does. The other question is if the SwinSID won´t crash and react correctly - in a C64, the SID is only updated 50-60 times a second, while the MBSID updates it more than 1000 times a second. So it could well be that the SwinSID is overwhelmed with all the data it gets. Only way to find out is either build one and try out yourself or ask the programmer.

Seppoman

3

yeah, that was what I thought, the way the midibox uses the sid is much more intensive than how the C64 uses it. Which makes me suspect it could not work the way it should…

Taking that off, the SwinSID designer states that the thing has much more features, like wavetable synthesis and other, but as it doesnt have software support, he says, then the only use you can give to a SwinSID is replace a real SID, at least temporally or for experimenting. It could interesting tho, to make use of those special features in a Special MidiBOX for SwinSID, but of course that dream could be real only if the mastermind of midiboxes is interested :wink:

You are missing these:

1 - People could want to have a synth without having to carry a laptop, and even if there tons of soft plugins available, lone hardware is still hardware.

2 - no SID softsynth have the amount of IN and OUT that the midibox SID has. Due to that, you can’t achieve in software nor even half the sounds you achieve with the midibox SID.

3 - LOL, did I read well? you don’t have to program the AMTEL, the hex file is available in the site. Just burn and you have a SID wannabe ready for it. Also the board seems simpler if you already built any midibox.

4 -The sound doesnt tell me bad things… it sounds different of course, the filter could not be even near, but again, you still have a synth in your hands, no computer involved and no C64 cannibalizing needed. BTW, the differences I found in the ogg demos…its evident that the SwinSID had its built in reverb turned on during the recording of those. The reverb alone could be a good reason for going for it… I think I could dare… if it doesnt work, then the solution is simple: get a real SID and replace the SwinSID. I could still use it to build the portable sid player… not as fun tho…

Mmm, to buy a C64 internationally, there’s no way for me I’m afraid. There’s no Pay Pal in Uruguay, but me and my family we don’t have credit card btw. Moreover, the customs could ban everything that is introduced to Uruguay making the dispatch a very tedious and costly burocratic process so… I’m limited to an FM box, or getting the AMTEL chip, or, try to get a C64 somehow.

I still can get the packages from my mother, since its person to person box and even if they will open it to see what the hell is in there, an old C64 wouldn’t be attractive enough ban, specially if its scratched etc. Here, the prices of vintage computers are really high, almost double what the AMTEL chip + burner costs, but however, there are tons of MSX, and no C64 for sale. :frowning:

4

You are missing these:

1 - People could want to have a synth without having to carry a laptop, and even if there tons of soft plugins available, lone hardware is still hardware.

Yeah, but if I want hardware, I also want the thing to sound like hardware :slight_smile:

3 - LOL, did I read well? you don’t have to program the AMTEL, the hex file is available in the site. Just burn and you have a SID wannabe ready for it. Also the board seems simpler if you already built any midibox.

Off course with “program” I meant to upload the hex-file… As the guy sadly doesn´t release his source code, the other meaning of “to program” doesn´t make sense here. Anyway, when you follow this forum long enough, you´ll see there are a lot of people struggling hard to get “only” the MBSID working - both hardware and uploading software. So for them learning everything for two platforms won´t exactly increase their success rate…

The TDA1543 DAC used by SwinSID seems to be discontinued. I had to search for 20 minutes to find a supplier in Germany. But  that was probably easier than finding a SID in Uruguay :-. I feel with you and wish you good luck :slight_smile:

Seppoman

5

I’m stuck too, its not available nowhere here, nor even in Spain  :-\

However, its only a DAC, there should be an alternative… a modification to the board may be necessary tho…

Still, not going to give up, with or without a SID, I’m building the FM first.  :wink:

6

My thought about SwinSID was to use it to replace the SID’s I taken out of C64’s - might even be a novelty sale value. I wonder if Prophet 64 will work with SwinSID. I might just have a go at that…

If I find a cheap source of A->D’s I’ll post it in the ‘fleamarket’.

7

Hehe another VSE member here. I didn’t know you were building the SID. I’ll keep my eye out for another C64 here…I got mine for $5. I’m not sure how much shipping would be to Uruguay though. It’d probably be cheaper just to ship The SID itself.

Well I’ve got to go test out my OLED screen.

8

LOL, I feel like at home in this forum, I think that with my knowlegde on programming and electronics I could fit better in here.

What I’m building is the FM, but if you think the price of shipping the sid alone is low enough, then you are welcome. Still, I want to make the FM first and if I succeed then I would follow with a midibox sid.

9

Hi I’m the creator of SwinSID. This thread looks very interesting so i decided to join.

First of all SwinSID was created to work best with C64 but should work well in any SID compatible device. It uses a bit different wave shapes and only a digital aproximation of 1MHz SID output so it dosen’t sound like SID and will never be.

As Seppoman said, SwinSID is slowing down, when a several thousand of requests is sending to card. I can’t say where is the limit, but almost all c64 tunes works well.

TDA1543 is really rare to find, but also very cheap (1,5 euro ) My first prototype was working  on a AD1868. TDA1543 can be simply replaced by any stereo DAC with I2S interface without code change. Parallel 8 Bit output is also avaible.

I can make some changes in SwinSID to better fit your needs for example turning off pseudo reverb can give an extra CPU power for noise generator. If i decrease sampling frequency and add new address line there is possibility of 6 channel  2SID in 1SwinSID mode. Unfortunately i can’t enable all these features in one time due to CPU limitations.

Thanks for your interest

10

Welcome to the forum! :slight_smile:

Would it also be possible to provide a second WR# line instead of an additional address line? This would make your chip compatible to the MBSID V2 stereo SID design (see http://www.ucapps.de/midibox_sid_manual_l.html for sound examples)

Best Regards, Thorsten.

11

I can make some changes in SwinSID to better fit your needs for example turning off pseudo reverb can give an extra CPU power for noise generator.

Reverb is ok, maybe a way to enable and disable it?

I think you should join TK and see if both can make a new synth together :wink: so maybe all the swin sid capabilites pops up, this way it doesn’t have to be a simple sid simulation but something else, more complex, and less specific, right?

12

:o that looks promissing! could be a real alternative to the original chips  ;D hope so …

13

Nikko electronics in the UK have the chip at £1.29 plus VAT and Carriage.

I could do a bulk buy if enough were interested.

see: http://www.dalbani.co.uk/catalogue/product_details.php?id=25337

Added

Voti has them too (should have looked first!), cheaper at 1.50 Euro

http://www.voti.nl/shop/catalog.html

Mike

14

thats about as much as it worths

15

SwinSID is working asynchronously so it ignores CLK and WR lines. Only CS is checked. One of the WR or CS lines can be used as a most significant address bit when we add them with AND gate.

It is very hard to do a good synthesizer from a slow 8 bit CPU. SwinSID can simulate a SID registers which is slowing down, but the SwinSID2 is specially designed to achieve best results from an AVR. There are 6 oscillators which can be joined in chain to get FM, AM and other modulations. I think it has potential but there is no software and project was abandoned.

I have done a 2x oversampling mode instead of interpolation in SwinSID recently. Now it should sounds more like SID. (Its internal mixing frequency is now 62,5 KHz.) I will release updated firmware in few days.

16

I also see that your synth chip has potential, and from my side it would be relatively easy to add support for additional sound registers. So, the infrastructure is already there.

CS line: I think that an alternative addressing mode could help, so that only one CS line is required.

The advantage of two CS lines (the addressing scheme I’m using) is, that I can write to a certain SID seperately, but also access two SIDs the same time. This speeds up register transfers and ensures synchronous configuration (important for stereo sounds, especially when the TEST flag is toggled to reset the oscillators)

For the case that it is impossible to provide two CS lines from your side: would it be possible to provide two additional address lines, which allow following access modes:

[tt]

A6 A5

  0  0  SID left channel

  1  0  SID left channel

  0  1  SID right channel

  1  1  SID both channels

[/tt]

(basically this is propably already the same addressing you are using, only difference is, that by setting A6 together with A5, a register access will be forwarded to both SIDs)

Or alternatively: do you think, that a different way to write into emulated SID registers could improve the overall performance? E.g., how about SPI, I think that AVR provides such an interface? By using SPI, the 74HC595 shift registers wouldn’t be required anymore at the MIDIbox side, and the MBSID firmware could transfer register values directly to your synth chip

Best Regards, Thorsten.

17

I’m having problems locating some reasonable priced SID chips in the UK, mainly because I don’t drive and P&P on ebay is so much. All the same, i’m holding out as I want the original SID sound. I’ve been thinking about this PIC synth and all those pillaged C64s that must be laying around. If this could be made cheaply then it would be good to replace the SID chips which have been removed from C64s and therefore make a fully functional console to sell on/give away rather than scrapping it.

          G

18

I will try SwinSID and give feedback how it works with MBSID

Btw.: ATMega 8515 is available for ca. 2 EUR at Reichelt, + the other parts makes ca. 3..4 EUR in total

I will canibalize the DAC from an old soundcard (TDA1387 seems to be compatible)

So, it’s indeed an interesting experiment which doesn’t cost much money :slight_smile:

Best Regards, Thorsten.

19

Indeed, if it could be shoehorned into the MBSID application it would RULE. Even if it doesn’t sound like a SID 100%, it would be another useful voice. Maybe even good enough to deserve it’s own dedicated application??

20

Even if it doesn’t sound like a SID 100%, it would be another useful voice. Maybe even good enough to deserve it’s own dedicated application??

Exactly, and I am very happy about it!  :slight_smile:

Swinkels, welcome to the forum!