Posted By
Bionic
on 2003-12-30
|  Sid-Card experiments
I started tinkering with a new SID-card again. I built a prototype that allows
me to do some experiments with the interface of the SID to the Plus/4.
Some things that bothered my about the original SID-Card where:
-Works only with 8580 (6581 sounds better  )
-The SID is not clocked at the same clockrate as in the C64
-The interface circuit is "interesting" and can not be garuanteed to
work under all circumstances (different components), so I am using more
reliable handshaking.
Ok, here are my audible results so far:
http://www.tu-harburg.de/~setb0209/cpu/images/sidsamples/
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Posted By
Bionic
on 2004-01-03
15:44:23
| Re: Sid-Card experiments
I added a picture of the prototype for those who are rather
into visuals. In the meantime I added a 512kb flash, which
can be accessed pagewhise as external ROM cardridge,
therefore giving you the ability to store around 4 disksides
of software in it.
Btw.. only 4 people downloaded one or more of the mp3s,
one of them was me. Seems that Plus/4 users are not that
much into SID as one may have guessed?
Well, there is a slight chance of getting this beyond proto-
type state, which would mean that you could buy a new
SID-card. The question is, does anybody on Plus/4 care
about more accurate SID sound, or the ability to use a
6581? What do you think about a 512kb flash disk?
How much would you be willing to pay for this?
Comments appreciated, and if possible more than the
yes/no the poll already offered Building and developing
the prototype is less than 10% of the work required to
bring a finished product to you, and personally I do mainly
benefit from these first 10% (yes, thats the fun part). So
there is some motivation required for the remaining 90%
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Posted By
Bionic
on 2004-01-03
15:47:24
| Re: Sid-Card experiments
P.s.: I am also interested in ideas about additional features that
you may find useful.
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Posted By
SVS
on 2004-01-04
11:59:13
 | Re: Sid-Card experiments
Good wark Bionic!
I think the Flash 512K is a good idea, that you could improve with the ability to switch inside it different O.S.s. I mean if I got a card with a flash containing for example OS96, Standard OS, and SVS-OS, I should be glad to switch one of them at a snap-time
Another idea coming to me in this moment is a RAM disk (or something like it).
I'm thinking about...
See you
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Posted By
Luca
on 2004-01-07
02:36:33
 | Re: Sid-Card experiments
Tremendously great job, Tim!
Now's time to spread the word like hell!
About prices, well, seems to be obvious that the cheaper will be, the best it is. Starting from about 40 Euros (older SIDcard price) you must decide how floating this price is.
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Posted By
MC
on 2004-01-07
03:56:28
 | Re: Sid-Card experiments
Congrats Bionic, decent job and good ideas
30-40 Euro seems like good price! Or ship it without a SID for a much lower cost.
How much does that flashmem add to the price?
How can you access that memory from the C+4 side? Working like a memory expansion would be great  But i guess that flash is too slow for that
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Posted By
Luca
on 2004-01-07
04:24:12
| Re: Sid-Card experiments
Tim, which are the main differencies between THIS card and the Solder's one?
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Posted By
Bionic
on 2004-01-07
06:19:34
| Re: Sid-Card experiments
Well, I assume 40Euro is the lowest boundary, WITHOUT a SID. But I have to look into this later when I got a prototype on a custom PCB. The problem of low volume manufacturing is still unsolved..
The flash adds around 4-5Euro to the price.
Differences to Solders card:
-Runs at actual C64 SID clock (software configurable)
-More efficient voltage converter, hence a 6581SID can be used. But I have yet to test this with a real Plus/4 power supply.
-Supports emulation at $D400, so that frequency/wave converters can be circumvented. (software configurable)
-256kb or 512kb flash
-Uses more reliable handshaking (not relevant to enduser)
-No support for mouse/joystick/paddle..
-It is not possible to read the SID registers anymore, but this was probably a bit broken on the original card, too.
The flash can be accessed as the first external ROM bank, so it is similar to the 3plus1 software. This means it is unfortunately not possible to replace the internal kernal It is also not possible to use it as external RAM, as the flash is accessed pagewise. No single byte writes are possible.
I thought about inclluding an external 256kb memory extension. But so far I am not sure how to replace the internal memory with external one (may be possible, since this seems to be what the external 64kb extensions do). In addition it is not possible to maintain compatibility to solders internal 256kb extension as this would require cutting some lines on the Plus/4 PCB.
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Posted By
Luca
on 2004-01-07
06:49:47
| Re: Sid-Card experiments
Is it possible to select if $D400 or $FD40($FE80)?
I paid 40 Euros WITH the 8580 on, but I feel your assuption is a good one, you're right. You know, I'll buy it at any price!
The correct c64 clock feature is a real great one!
Flash memory is good too, but I can't picture its use: can I use it like an expansion (thus I may watch your 256K demos all the time? )
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Posted By
Bionic
on 2004-01-07
07:07:53
| Re: Sid-Card experiments
Luca: Yes, you can select the SID baseaddress
Solders SID-Card was much cheaper to build because:
-He used low quality PCBs and had a really cheap supplier, this is not available anymore
-He did all the soldering byself.. presumably no option for me (time..).
-The new SID cards uses less, but more expensive components. But well, the difference is in the order of 1-2EUR
-You were still able to buy SIDs back then.
-Everything was cheaper ten years ago
The flash is similar in function to solders internal and external sram cards. You can use it to store software and external rom modules (like "financial advisor" ) and access them instantly.
Btw. it is probably possible to integrate a freezer, similar to the retro replay on the C64, at hardly any additional cost. But somebody had to figure out the required software and circuits..
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Posted By
Luca
on 2004-01-07
07:28:40
| Re: Sid-Card experiments
Well, why waiting? I'm here with an empty hand and money in the other one!
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Posted By
bubis
on 2004-01-07
17:42:51
| Re: Sid-Card experiments
I would pay 40-60 Euro for a card with 256 kb flash (without SID)!
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Posted By
Gaia
on 2004-01-08
04:22:44
| Re: Sid-Card experiments
There's a freeze bit in the TED (bit #5 of $FF07). This stops the counters and the TED will only perform RAM refreshes. This could be exploited easily for a freeze functionality.
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Posted By
SVS
on 2004-01-08
08:12:21
| Re: Sid-Card experiments
>>There's a freeze bit in the TED (bit #5 of $FF07)
But unfortunately I figure it does not stop the processor; we should find something able to stop the processing like a IRQ selfcalling or so...
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Posted By
Gaia
on 2004-01-08
14:17:28
| Re: Sid-Card experiments
No more IRQ is possible if the TED is halted. Besides the TED can stop the processor thru the RDY signal, and I believe that is here what happens.
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Posted By
Bionic
on 2004-01-09
05:21:56
| Re: Sid-Card experiments
Well, I am afraid a freezer on the Plus/4 is not that simple. The key point is that you map your own ROM to the interrupt pointers. Apparently there is an easy way to do this on the C64, but I am not aware of one for the Plus/4.
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Posted By
Mike
on 2004-01-09
19:01:57
| Re: Sid-Card experiments
Just my $0.02... When at DMA, Dave was trying to make an Amiga Action Replay, and he mapped in 4 bytes of ROM in hardware - (jump vector)...by fudging the address/data lines. He didnt use any kind of ROM selector.
If you do this, you can make the plus/4 jump anywhere you want and set up anything you want.
This is how C64 carts work too - so datel told him at the time.
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Posted By
Hans
on 2004-01-11
08:00:47
| Re: Sid-Card experiments
Well, now I just have to know how to "fudge" datalines If you refer to forcing them to a level: This does only work for pulling them down, you can not force them to a one without damaging one of the chips...
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Posted By
Mike
on 2004-01-11
12:27:28
| Re: Sid-Card experiments
Excuse my lack of anything resembling any technicall understanding. I dont know electronics, Im just reciting from memory a conversation I had with Dave Jones some 14 years ago
This method was also confirmed by Datel... so while I may not have the method "exactly" detailed, it was done by forcing either the address lines to point to your ROM (or something) or forcing data down there... I'll admit... (please read in faulty towers voice) "I know nothing!!!" :D
I would pass on his email, but he barely responds to me, even though I worked with him for 10 years!...so he'll never answer anyone else... Just thought Id let you know what I heard from people that had actually done it.........I thought it may help - perhaps not.
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Posted By
Luca
on 2004-03-16
07:47:04
| Re: Sid-Card experiments
Me and some c64 ppl are waiting for your decisions, Tim
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Posted By
Bionic
on 2004-03-16
12:12:11
| Re: Sid-Card experiments
Luca: the parts for a real prototype are at home. I just have to finish the PCB layout and get the PCB made.. Unfortunately this does not go well with writing my final thesis at the same time.
Regards "mass" production - so far it seems that the amount of required parts due to the analog part and dc converter drives the cost of automatic assembly quite high. I do not have exact figures yet but its way more then 50euro..
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Posted By
Luca
on 2004-03-17
02:27:10
| Re: Sid-Card experiments
When will you a brandnew graduate?
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