Keyboard

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A photograph of the VIC-20 computer's keyboard as seen on the initial Japanese production run. These keyboards are also known as "PET" style keyboard because of their feel and appearance.
The same keyboard removed from the VIC-20 case. Image credit Mark Creswell.

The keyboards used in VIC-20 computers were manufactured for Commodore by Matsushita Corporation of Japan. Those used on the very first VIC-20s were almost completely flat-topped and identical in shape to that of Commodore's PET computer (however, on the VIC-20 the PET's number pad was replaced by four wide function keys). The keyboards on later VIC-20s were manufactured with slightly concave tops. The concavity of the “F” and “J” keys was slightly more prominent to provide tactile feedback for touch-typists seeking the “home” position.

The VIC-20's keyboard largely conforms to the QWERTY standard, however it differs from modern computer keyboards in several aspects:

  • There is no ESCAPE key, although a left pointing arrow in the upper left corner of the keyboard can be made to function this way in software.
  • There is no cursor "T" pad. Instead, there are two cursor control keys. One for UP/DOWN and another for LEFT/RIGHT. Pressing a cursor key with or without the SHIFT key held down toggles that key's function.
  • There are no ALT keys.
  • A Commodore logo key (also called the "CBM" or "Chickenhead" key) enables special functions when depressed simultaneously with other keys. Some of these functions are: toggle Upper/Lower case characters and enable PETSCII graphics).
  • A RUN/STOP key on the VIC-20 can be used to start and stop the execution of BASIC programs.

There are several variations of the VIC-20's keyboard:

  • English standard version.
  • Japanese version (seen on VIC-1001) with kana (Japanese characters) and a Yen currency symbol.
  • Scandinavian keyboard (with Scandinavian letters).

The VIC-20 keyboard is electronically and physically compatible with that used in the Commodore 16 and Commodore 64 model computers (although the C16 keyboard has some keys labelled differently). The keyboard of the VIC-20 connects to a row of pins on the VIC-20 motherboard by means of a long plastic female connector. This connector carries ROW and COLUMN signals from the keyboard matrix.

Pin assignments of the VIC-20's keyboard connector.


Internally there are graphite, carbon coated, spring loaded plungers under each key. When a key is depressed the plunger touches a corresponding metal contact on a printed circuit board, thereby sending a signal to the CPU.

Detail of the carbon coated plungers on the underside of each key. Image credit Mark Cresswell.
Detail of metal contacts on the surface of the printed circuit board contained inside a VIC-20 keyboard. Each contact lies beneath a key and plunger. Image credit Mark Creswell.


Keyboard input/output is controlled by one of the VIC-20's VIA and CIA chips. If one of these chips are bad, keyboard problems (such as every other key not responding) will manifest themselves.

The VIC-20 keyboard has all of the PETSCII graphic characters printed onto the front face of each of the keys (the side facing the user). Holding down either the COMMODORE or SHIFT key while pressing a PETSCII graphic key will cause that symbol to appear on-screen.

Drawing showing the location of letters, numbers and custom PETSCII character on the VIC-20's keyboard

Over the manufacturing lifespan of the VIC-20, three different fonts were used to print the letters and symbols on the key-tops:

  • Earliest VIC-20 keyboards used the Microgramma Extended font which was also used on PET computer keyboards.
  • Second generation keyboards used the Eurostile font which was less-bold, but still square in shape.
  • Third generation keyboards used a tall, thin font similar to Helvetica Narrow. This font also was used for the first Commodore 64 (breadbox style) computers.
The "PET" style keyboard used on the VIC-1001 and early VIC-20s featured the "Microgramma Extended" font. The key-tops are almost flat and very square shaped.
The second VIC-20 keyboard used a square but thinner font known as "Eurostile". The corners of the key-tops show slight rounding.
The final keyboard featured a font similar to "Helvetica Narrow". The key-top corners were very rounded had a pronounced concavity.


The early "PET" style keyboard was lower in profile when compared with the two later VIC-20 keyboards.

"PET" style keyboard as seen from the side. Note the low profile, especially in the top number row.
Side profile of the later "Eurostile" & "Helvetica Narrow" keyboards. Note the much taller profile of the keys in the top and bottom rows.


Most of the VIC-20's keys were moulded in dark-brown plastic, with the function keys being a lighter brown/mustard. However, some very late production production VIC-20s were shipped with Commodore 64 grey coloured function keys. It also seems that a few extremely early Commodore 64 prototypes and production-line computers were assembled using VIC-20 coloured brown/mustard function keys.

Most VIC-20s were produced with brownish/mustard coloured function keys. Depicted are those from a first generation VIC-20 keyboard ("PET" style).
At the very end of the VIC-20's production life, Commodore shipped some VIC-20s with the grey function keys of the Commodore 64 (as shown above).


LINKS:

VIC-20 keyboard disassembly and repair.