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tlr
Registered: Sep 2003
Posts: 1787 |
How do I reliably detect 6581/8580 sid?
There was an article in C=Hacking, but that does not work very well in VICE for example.
Maybe VICE's emulation is borked though.
I remember seeing a detailed analysis of the waveforms somewhere, but I can't seem to find it now.
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Necronomfive
Account closed
Registered: Dec 2004
Posts: 20 |
Quote: High-speed according to Wikipedia, yes. It can also stand for High-density CMOS. Also HMOS-II is obviously an improvement over HMOS.
I agree about the 9V/12V though.
Great link! I hadn't seen that sid-page actually.
Thanks!
However, MOS/CSG NEVER produced any CMOS VLSI´s, since Commodore did not care to invest any money to modernize the chip plants. The C64 was selling like hot cakes, so why bother?
They renamed HMOS to HMOS-II, because the only chips produced at their plants in HMOS (73xx series) ran unreliable and died easily. The first batches of C16/C116/Plus/4 Chips were done in that process. They improved that process and called it HMOS-II (83xx, 85xx series)
This is the reason, why the 8361 Agnus in the Amiga 1000 had only 48 pins and needed LOTS of TTL/GAL supply logic on the mainboard, because they WERE NOT ABLE(!) to bond PLCC84 packages at this time, because they were still using the old equipment from the seventies for chip fabrication. After 1987, they never produced anything above PLCC84. The only CMOS Chips in the AGA Chipset were done by other companies (VLSI, HP), since CSG could not handle it.
Glad you like the page. :) |
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Raf
Registered: Nov 2003
Posts: 343 |
by the way how about 6582? can it also be recognized this way? and what's actual difference among 6581 and 8580? I've heard 6582 is NMOS 8580 made after 1991 to replace old 6581 , but this seems to be fake as I've found a photo of 6582 from 1986... never seen or heard 6582 live though... |
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Necronomfive
Account closed
Registered: Dec 2004
Posts: 20 |
Quote: by the way how about 6582? can it also be recognized this way? and what's actual difference among 6581 and 8580? I've heard 6582 is NMOS 8580 made after 1991 to replace old 6581 , but this seems to be fake as I've found a photo of 6582 from 1986... never seen or heard 6582 live though...
There is no audible difference between 6582 and 8580. Both Chips share the same design, have the same filter characteristics, the same sample "fix", and seem to have come out around the same time (1986). Why they actually labelled the same design under 2 different names is really beyond me, since labelling it 6582 bears the danger to confuse it with the 6581 and put it into the same socket.... |
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Steppe
Registered: Jan 2002
Posts: 1510 |
So the rumour that 6582 is essentially an 8580 with digi-capabilities is wrong? |
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Necronomfive
Account closed
Registered: Dec 2004
Posts: 20 |
Quote: So the rumour that 6582 is essentially an 8580 with digi-capabilities is wrong?
Yes. When Jens (Schönfeld) got a batch of 6582 chips, the tests turned out really disappointing. The 6582 is just an ultrare package variant of the 8580. |
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Hoogo
Registered: Jun 2002
Posts: 105 |
I remember a very different way how to distinguish betwenn old and new sid. The sid does not support reading from his normal registers, but still you can read a written value for a while. That time is different for old and new sid. |
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tlr
Registered: Sep 2003
Posts: 1787 |
@Hoogo: I remember that too.
It surely won't work in VICE though. |
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Hein
Registered: Apr 2004
Posts: 946 |
Quote: @tlr: About the tests me and twoflower did.. We're not talking about $05, but of $50.... that is.. simply the combined waveforms.. Pulse+Tri. Nothing new, apart from the fact mentioned that 8580 machines seem to differ (and that 6581s aren't 100% reliable under all possible prior register settings, but that doesn't really matter, as I already said).
I don't really understand the 8580 chip difference though. I mean.. I thought the oscillator reading stuff was done on values strictly internal to the SID, but either the 8580 chips are different or the surroundings of the chip really have an influence on what is read from osc3 output... Too bad I'm not very good at electronics to have an educated standpoint in that matter..
Writing a cycle later can make a difference... Don't know if that's the case, but I can imagine that testing on a real c-64 requires cycle precise testing. |
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Raf
Registered: Nov 2003
Posts: 343 |
Quote:
There is no audible difference between 6582 and 8580. Both Chips share the same design, have the same filter characteristics, the same sample "fix", and seem to have come out around the same time (1986). Why they actually labelled the same design under 2 different names is really beyond me, since labelling it 6582 bears the danger to confuse it with the 6581 and put it into the same socket....
but then I have 6582 datasheet and monolytic capacitors on pins 1-2 and 3-4 are other than for 6581 and 8580 , thus it should make differnece on filter... any ideas? |
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Necronomfive
Account closed
Registered: Dec 2004
Posts: 20 |
Quote: Quote:
There is no audible difference between 6582 and 8580. Both Chips share the same design, have the same filter characteristics, the same sample "fix", and seem to have come out around the same time (1986). Why they actually labelled the same design under 2 different names is really beyond me, since labelling it 6582 bears the danger to confuse it with the 6581 and put it into the same socket....
but then I have 6582 datasheet and monolytic capacitors on pins 1-2 and 3-4 are other than for 6581 and 8580 , thus it should make differnece on filter... any ideas?
It has always been a BIG difference what Commodore wrote in their Datasheets, and what was actually done in the real machines. ;) Like claiming that combining waveforms will result in a logical ANDing, which is absolutely not true.
Of course, it makes a difference if you apply different filter capacitors to the 6582 as it would make a difference if you would apply them to the 8580. What counts is how it sounds under the same conditions, and both 6582 and 8580 sound identical. |
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