Vic 20's Keyboard font ??

carlsson · Post by **carlsson** » Wed Feb 04, 2009 3:43 am

Perhaps your C64 has a broken 6526? I used to have a very early C64 too and had no problems cross-swapping keyboards between models.

Dimlow · Post by **Dimlow** » Wed Feb 04, 2009 4:10 am

If that's the case, then why does the keyboard on it work, and why does it work with another c64 keyboard, but not the vic 20's, check out the schematics! i posted

ral-clan · Post by **ral-clan** » Wed Feb 04, 2009 6:16 am

Dimlow wrote:Just checked the schematics. i am right!

VIC 20

http://eab.abime.net/picture.php?albumi ... tureid=729
C64
http://eab.abime.net/picture.php?albumi ... tureid=728

The Col and ROW lines are swapped

Wow, if you are correct this is significant. Not to be a Doubting Thomas, but rather just to be careful (before adding to to the Wiki), could someone else with electrical knowledge please confirm this info? A second opinion would be helpful.

eslapion · Post by **eslapion** » Wed Feb 04, 2009 7:44 am

Dimlow wrote:Just checked the schematics. i am right!

VIC 20

http://eab.abime.net/picture.php?albumi ... tureid=729
C64
http://eab.abime.net/picture.php?albumi ... tureid=728

The Col and ROW lines are swapped

The ROW and COL are swapped in the way they are connected from the board's connector to the CIAs/VIAs ... the keyboard itself (disconnected from the computer's board) is perfectly identical electrically.

The kernal in each respective computer accesses the IO lines accordingly...

I can assure you that my VIC-20's PET style keyboard works perfectly well on my 64...

ral-clan · Post by **ral-clan** » Wed Feb 04, 2009 8:37 am

But how does the connector look? I forget. But if I recall correctly, VIC/C64 keyboard connectors are one long solid piece of plastic, not a two part connector. So if you had a keyboard where the wires for CIA & VIA were swapped, you couldn't just plug it into a "normal" VIC or C64. So, even though it is just a seemingly arbitrary and odd swap of lines, it still is a variation worth mentioning.

Why Commodore would do this is another mystery.

Dimlow · Post by **Dimlow** » Wed Feb 04, 2009 9:54 am

Ok, Agreed, the keyboard is electronically the same. BUT they are connected with the ROW and COL lines swapped. So if you wanted to swap over keyboards from a VIC 20 to a 64, some rewiring is needed. Its not a straight swap. This i think needs to be pointed out in the wiki if you are going to claim that they are electronically compatible.

The connectors ARE the same, a single row of pins.

ral-clan · Post by **ral-clan** » Wed Feb 04, 2009 10:25 am

Dimlow wrote:Ok, Agreed, the keyboard is electronically the same. BUT they are connected with the ROW and COL lines swapped. So if you wanted to swap over keyboards from a VIC 20 to a 64, some rewiring is needed. Its not a straight swap. This i think needs to be pointed out in the wiki if you are going to claim that they are electronically compatible.

The connectors ARE the same, a single row of pins.

The question is not only why would Commodore do this, but how many C64s were made this way - a minority or ALL C64s?

Once I get the answer to this I'll add the info to the article, as I think it is significant.

Unseen · Post by **Unseen** » Wed Feb 04, 2009 10:29 am

Dimlow wrote:BUT they are connected with the ROW and COL lines swapped.

The keys don't care which end is called "row" and which end is called "column".

The keyboard matrix as seen by software differs between the VIC20 and C64, but that's just because some lines between the CIA and the keyboard connector were swapped around. The matrix as connected to the keyboard connector is exactly the same.

So if you wanted to swap over keyboards from a VIC 20 to a 64, some rewiring is needed. Its not a straight swap.

It is a straight swap and always has been.

I wonder why such strange rumors can even get started when it's so simple to check the facts with a few queries in your favorite search engine...

ral-clan · Post by **ral-clan** » Wed Feb 04, 2009 10:58 am

Wow....so it's just a mislabelling on the schematic (a swap of the names ROW and COLUMN). There's nothing electrically different.

Sheesh. THAT was confusing for a second.

Dimlow · Post by **Dimlow** » Wed Feb 04, 2009 11:02 am

Ok, so explain to me why my vic 20 keyboard does not work in my C64

Unseen · Post by **Unseen** » Wed Feb 04, 2009 11:08 am

Dimlow wrote:Ok, so explain to me why my vic 20 keyboard does not work in my C64

Sorry, my crystal ball is currently out-of-order. Maybe you can clarify the situation yourself, for example by listing more symptons than "does not work"?

Dimlow · Post by **Dimlow** » Wed Feb 04, 2009 11:12 am

Perhaps if you had taken the time to read my earlier posts, you would have no reason to be so pedantic

Unseen · Post by **Unseen** » Wed Feb 04, 2009 11:26 am

Dimlow wrote:Perhaps if you had taken the time to read my earlier posts, you would have no reason to be so pedantic

The only claim of yours I can see in this thread is "does not work". You tried to support the claim about keyboard differences with two extracts from the schematics of the two computers, but the VIC20 extract does not show the correspondance from the 6522 pins to the pins of the keyboard connector which makes it useless for supporting or refuting the claim that the keyboard matrix of the two system differs.

The latter part doesn't really matter though because you neglected to consider the most important detail about a keyboard matrix: The actual key assignments. Maybe you can take a look at this C64 matrix and the VIC20 matrix listed in this text file, compare them, re-sort one of them because the bit assignments for both the column and row ports were slightly scrambled in the C64, compare them again and tell us where the keyboard matrices of a VIC20 and C64 differ.

And besides: I like being pedantic while diagnosing problems. It usually reduces wasted time.

Dimlow · Post by **Dimlow** » Wed Feb 04, 2009 12:10 pm

http://www.zimmers.net/anonftp/pub/cbm/ ... 1027l2.gif

http://www.zimmers.net/anonftp/pub/cbm/ ... A-left.gif

eslapion · Post by **eslapion** » Wed Feb 04, 2009 12:39 pm

Dimlow wrote:Ok, Agreed, the keyboard is electronically the same. BUT they are connected with the ROW and COL lines swapped.

So what? The keyboard scanning routines addresses the IO lines of the VIA/CIA chips accordingly...

So if you wanted to swap over keyboards from a VIC 20 to a 64, some rewiring is needed. Its not a straight swap. This i think needs to be pointed out in the wiki if you are going to claim that they are electronically compatible.

A completely FALSE claim... that's it.

The connectors ARE the same, a single row of pins.

If you take the keyboard alone, the connector is the same and so is the way the keys are wired to it.

The difference is only between the connector and the IO chips... but guess what? It doesn't matter because the kernal of each machines is programmed accordingly.