6562/6563 datasheet

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rga24
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6562/6563 datasheet

Post by rga24 »

I've been going through my collection of Commodore hardware and documentation and found the datasheet for the 6562/6563 VIC chip. Not sure if this is actually online yet so I thought I'd check.

It's a 40 column capable VIC chip that basically runs at twice the dot clock frequency and twice the memory bus speed of the 6560/6561. The register file is very similar to the 22 column VIC, significant differences being as follows:

Border colour may be any one of the full 16 colour palette
8x32 character mode instead of 8x16
4 bit video matrix address instead of 5
3 bit character generator address instead of 4
Three sound channels instead of four, each with independent 4 bit volume
Channel 1 is sawtooth
Channel 2 is pulse
Channel 3 is square / noise

I'm sure I saw a picture of one of these on the web at one point. Must be quite a rare chip unless there is an application I am unaware of.
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Post by Mike »

rga24 wrote:I'm sure I saw a picture of one of these on the web at one point.
It is linked to on this page, together with some other info: http://www.floodgap.com/retrobits/ckb/secret/vic40.html
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Re: 6562/6563 datasheet

Post by lance.ewing »

I'm resurrecting a very old thread here as I think it merits more discussion now that we're starting to look at the 6561 in more detail.

There appear to be two different datasheets for the 6562/6563 VIC chip. One is the standalone datasheet on various sites, e.g:

http://archive.6502.org/datasheets/mos_ ... 63_vic.pdf

Until recently, I thought that that was the only one there was.

The other datasheet is the much more detailed version in the Commodore Component Data Catalog of 1981. It is very similar to the datasheet for the 6560/6561 but with the differences already mentioned in the first post of this thread, and possibly one or two others not mentioned in that list.

The first comment I'm going to make about this is with regards to the input clock for the 6563. Supposedly these chips were going to be drop-in replacements for the 6561, but how would that have worked if it required an input clock twice as fast as the 6561? It would require more than dropping it in. The NTSC version appears to have had the same input clock frequency though, so that presumably wouldn't have been an issue in that case.

The second comment is with regards to the similarity between the 6562/6563 and the 6560/6561. There are enough similarities that I started wondering recently whether we'd find evidence at the silicon level of there being some kind of hard-wired "switch" to configure it to be one or the other, and if this were to be the case then could the 6560/6561 handle a higher input clock frequency? This data catalog from 1981 came out about the same time as the VIC itself, so perhaps they already had a 40 column version in mind and had allowed for it in the chip design. Who knows. These thoughts started to fall apart though when I noticed the differences with the sound registers. Those are quite different from the 6560/6561. All the other differences could be accounted for by wiring things up slightly differently (e.g. getting the Reverse bit from a different register), but the whole sound area seems quite different. The changes aren't so trivial.

16 colour borders? 8x32 quadrupled characters? The 6563 would have been quite interesting. I wonder if we can convince Dave Seiter to let someone take some die shots of his 6562? It's not going to happen, is it? A bit too destructive to something that might be the only one of its kind.

Edit: I couldn't find the detailed spec as a standalone document on the Internet, so I've extracted the relevant pages from the 1981 catalog in to a separate PDF document and uploaded it here:

https://sites.google.com/site/mos6561vi ... 63_vic.pdf
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Re: 6562/6563 datasheet

Post by lance.ewing »

The 6562/6563 datasheet does seem to have been rushed a bit. They've mistakenly used the block diagram from the 6560/6561. A 6562/6563 block diagram wouldn't show CRA as a tone register, since it is instead a volume register.
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Re: 6562/6563 datasheet

Post by eslapion »

The 6562 appears halfway between the 6560 and the 6567. It doesn't support sprites, it doesn't use a multiplexed address bus for DRAM but it does offer a 320x200 display and supports more colors.

What baffles me is the claim it is a drop-in replacement for the 6560. The 6567 can display 320x200 or 40 columns of text with 25 lines because it can do 2 things:
- Cache 40 character codes so it doesn't have to re-read the character codes on every scanlines; it scans those codes once and then uses them for the following 7 scanlines
- Steal cycles from the CPU on the one scanline where it has to both read the character codes as well as the character generator pixel information

In the C64, the CPU was altered to support temporarily putting the CPU on hold for DMA access or VIC-II cycles stealing but the VIC-20's 6502 doesn't have such features so I am at a loss to explain how the new double res video chip might simply be a drop-in replacement.

If one was truly motivated to create a new double res video chip for the VIC-20 that is a real drop-in replacement which uses today's technology then I guess you could fit this new chip with a 1kByte cache which would read to cache all the character codes during the vertical blanking interval and offer a full 40x25 characters display while respecting the VIC-20's bus speed/access limits.
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Re: 6562/6563 datasheet

Post by Mike »

eslapion wrote:the VIC-20's 6502 doesn't have such features so I am at a loss to explain how the new double res video chip might simply be a drop-in replacement.
Quite simple (see page 2-96 in the data sheet): it would run CPU and memory subsystem at 1.8 MHz (i.e. effectively at double the speed as with the VIC-I chip).

What relieves me a bit is, that the 8x32 character mode is explicitly declared to support a full-screen bitmapped mode. That should take the wind out of anyone's sails who still tries to tell people, that a VIC-20 with the VIC-I in 8x16 character setup just doesn't do a bitmap.

That being said - before people start dreaming about what would be possible with the 62/63 they ought explore what can be done with the 60/61, on standard h/w, but also taking routes like the VFLI mod into account. Otherwise they are anyway just better served with using a C64 instead.
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Re: 6562/6563 datasheet

Post by eslapion »

Mike wrote:Quite simple (see page 2-96 in the data sheet): it would run CPU and memory subsystem at 1.8 MHz (i.e. effectively at double the speed as with the VIC-I chip).
So the answer is simple: it doesn't respect the VIC-20 bus speed limits...
What relieves me a bit is, that the 8x32 character mode is explicitly declared to support a full-screen bitmapped mode. That should take the wind out of anyone's sails who still tries to tell people, that a VIC-20 with the VIC-I in 8x16 character setup just doesn't do a bitmap.
Here we go again... :roll:
That being said - before people start dreaming about what would be possible with the 62/63 they ought explore what can be done with the 60/61, on standard h/w, but also taking routes like the VFLI mod into account. Otherwise they are anyway just better served with using a C64 instead.
I like to dream of a VIC-20 video chip that uses a large internal cache to provide 40x25 display while keeping the bus at approx. 1MHz. without the need to steal CPU clock cycles.
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Re: 6562/6563 datasheet

Post by Mike »

eslapion wrote:Here we go again... :roll:
:lol: If the shoe fits, wear it.
I like to dream of a VIC-20 video chip that uses a large internal cache to provide 40x25 display while keeping the bus at approx. 1MHz. without the need to steal CPU clock cycles.
Dream what you want. The hardware isn't there, and that is not going to change anytime soon.

You could, however, try to improve on your own programming skills. That would make many 'problems' a non-issue. If something can be realised on standard VIC-20 hardware with proper software, there's no need to dream up improved hardware to compensate for lack of those skills.
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Re: 6562/6563 datasheet

Post by eslapion »

Mike wrote:
I like to dream of a VIC-20 video chip that uses a large internal cache to provide 40x25 display while keeping the bus at approx. 1MHz. without the need to steal CPU clock cycles.
Dream what you want. The hardware isn't there, and that is not going to change anytime soon.
The hardware IS there and has been for a few years. What isn't there (yet) is the technical information.

It will come soon enough... don't worry.
You could, however, try to improve on your own programming skills. That would make many 'problems' a non-issue. If something can be realised on standard VIC-20 hardware with proper software, there's no need to dream up improved hardware to compensate for lack of those skills.
You've decided the VIC-20's display hardware can only be used in one very specific manner to display bitmaps and that's false too...

Perhaps you could study modern digital electronics and try to improve on your knowledge of what's available. That would make many 'problems' a non-issue.
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Re: 6562/6563 datasheet

Post by Mike »

You've decided the VIC-20's display hardware can only be used in one very specific manner to display bitmaps and that's false too...
If you really think that, then the OP in the thread 'A round-up of all known VIC-I display modes' should give an interesting read for you.

BTW, I wrote that text. :)
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Re: 6562/6563 datasheet

Post by eslapion »

Mike wrote:If you really think that, then the OP in the thread 'A round-up of all known VIC-I display modes' should give an interesting read for you.

BTW, I wrote that text. :)
It's funny, I vaguely remember setting the PETSCII text mode to display 23 columns x 25 rows back around 1985 for a simple BASIC "chase me" game.

I guess that's impossible according to you.

Technical sidenote: I was using a 3K RAM expansion and lowered the BASIC upper limit.

And BTW: This thread is supposed to be about the 6562/6563, not arguing about pointless details...
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Re: 6562/6563 datasheet

Post by Mike »

eslapion wrote:It's funny, I vaguely remember setting the PETSCII text mode to display 23 columns x 25 rows back around 1985 for a simple BASIC "chase me" game.

I guess that's impossible according to you.
Just read the first paragraph in that text:
Mike wrote:* 'PETSCII text mode': normally 23 rows @ 22 characters, glyph data taken from character ROM.

This is the mode all VIC-20 users are familiar with. Two fonts are provided (switchable with SHIFT+CBM): upper case+graphics or lower+upper case. The VIC chip can be programmed to show another number of rows and columns, but the full screen editor can only handle the 22x23 layout.
Emphasis added.
eslapion wrote:And BTW: This thread is supposed to be about the 6562/6563, not arguing about pointless details...
... and neither is it about dreaming of non-existent hardware.
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Re: 6562/6563 datasheet

Post by eslapion »

You're engaging in this battle of words just because I said you can have a greater vertical resolution in PAL vs NTSC on a VIC-20 ?

Man, you need some help...
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Re: 6562/6563 datasheet

Post by Mike »

eslapion wrote:You're engaging in this battle of words just because I said you can have a greater vertical resolution in PAL vs NTSC on a VIC-20 ?

Man, you need some help...
Do you really think my remark about the 8x32 character mode was specifically directed at you? m(
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Re: 6562/6563 datasheet

Post by groepaz »

LOL! get a room!
I'm just a Software Guy who has no Idea how the Hardware works. Don't listen to me.
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