Commodore VC-20 CR
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This nice machine was the beginning of the 'breadbin'-era! Behind it, the very first, white VC-1541 drive and manuals
(picture copyright by M.A.Grundke) |
Specifications
| Name | Commodore VC-20 CR |
| Codename | 'Vixen' (in early development stage), 'MicroPET' (the name with which it was first presented to public in 1980) |
| Made by | Commodore Business Machines (CBM) |
| Released | January 1981- the CR-version was released in 1982, and this particular machine was built in 1983 (indicated by the chips' production dates)
- first VIC-20 prototypes were presented on Summer-CES 1980 and were still called MicroPET
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| Serial-No. | WG A137593 |
| Board-info | |
| CPU | MOS 6502A (NMOS-process)- some machines were reported to use a MOS 6502B. The 6502A can be clocked with up to 2 MHz, the 6502B with up to 3 MHz (but not in the VC-20, of course)
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| Speed | 1.1084045 MHz (PAL)/ 1.0227272 MHz (NTSC) |
| RAM | - 5 KBytes
- 2 pcs. Fujitsu MB8128-15 (2Kx8)
- 2 pcs. Matsushita MN2114-3 (1Kx4)
- one additional MN2114-3 (1Kx4) used as video-RAM for VIC
- about 3.5 KBytes usable with BASIC
- expandable to 64 KBytes (via 3rd-party expansions)
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| ROM/ Native OS | 901486-01 Commodore BASIC V2 (8 KBytes)
901486-07 CBM VIC-20 KERNAL Revision 7 PAL-B (8 KBytes)
901460-03 character generator ROM (4 KBytes)- 20 KBytes ROM at all. That's why it's called VC-20...
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| Keyboard/ Layout | 66 keys/ US (QWERTY)- there were also a few localized keyboard variants, making use of a different character generator ROM, such as a swedish/ finnish, or japanese (katakana) layout (for the 'japanese VC-20', the VIC-1001)
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| Graphics | MOS 6561-101 'VIC' ('Video Interface Chip')- Max.Resolution:
- 128x128 pixels (with 5 KB RAM)
- 192x200 pixels (with >=8 KB RAM)
- Max.Colors: 16
- Text: 22x23 with graphical charset (29x35 with 'tricks')
- this machine's 6561 is a PAL-B version; its NTSC-M equivalent was the 6560, and was also able to output interlaced
- an interesting fact is that CBM, in an effort to make the VIC-20 a more professional machine, had already developed a 40 column-capable VIC (MOS 6562) in 1981. However, development was stopped because of the VIC-30 project (later C64) with its advanced VIC-II graphic chip
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| Sound | generated by VIC- three independant, programmable tone generators, one white-noise generator and an amplitude modulator
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| Media | - standard Audio-cassettes (via CBM VC-1530 'Datasette')
- 5.25" disks, 170 KBytes/ disk (all CBM serial drives; CBM VC-1540 and CBM VC-1541 were available these days)
- later: other CBM-drives via IEE488-interface
- later still: 3.5" disks (CBM 1581), 800 KBytes/disk
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| Input/ Output | 2x MOS 6522 'VIA' ('Versatile Interface Adaptor')- 1x 9 pin joystick/paddles/lightpen
- 48 pin female edge conn. cartridge interface (for memory-expansion or software cartridges)
- 5 pin round-DIN audio/ video (for monitor, RF-modulator)
- 6 pin round-DIN CBM serial IEC-bus (diskdrives, printers)
- 12 pin male edge connector CBM cassetteport
- 24 pin male edge connector 'user-port' (8 bit, programmable I/O, e.g. for modems, centronics-adaptors)
- 7 pin round-DIN power supply (9V)
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| Miscellaneous | - The VC-20 was Commodore's 'first strike' on the homecomputer-market. It was the direct predecessor to the Commodore 64 (aka VIC-30) and the cost-reduced Commodore MAX machine (aka VIC-10)
- Was called VIC-20 in all english-speaking countries and VIC-1001 in Japan; the VIC-1001 had additional japanese characters printed to the keycaps (katakana layout) and a different character generator ROM
- The name derived from its VIC-chip (later called VIC-I), ancestor of VIC-II (used in C64- and CBM-II series) and VIC-III (used in C64DX/ C65 prototypes). In Germany, it was called VC-20, the 'VC' meaning 'Volkscomputer' (to present it as a cheap BASIC-computer for everyone). The rumours that Commodore renamed it because VIC is an offensive word in Germany are absolute nonsense, btw
- Unlike its successor VIC-II (used in the C64-series), the VIC could not generate hardware-sprites; additionally, all VC-20 need an external RF modulator (CBM 1001027-03 for PAL-machines) to connect to a TV-set. Both facts didn't prevent the VC-20 from becoming a very popular machine
- This VC-20 CR (with ASSY 250403 board) was a cost-reduced version in which eight 2114 (1Kx4) SRAMs were replaced by two 8128 (2Kx8)
- There were several different versions of the VC-20, e.g. some with a '2 prong'-power connector or with different colored label. In addition to these,
there have also been two commemorative models, the Golden VIC (when the millionth VIC-20 was sold in the USA) and the Silver VIC (after two million machines had been sold)
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| Two VC-20 games: 'Caterpilla' (1983, left screenshot) was a nice Centipede clone by Ocean Software. Kingsoft's 'Firegalaxy' (1983, right) was a horizontally scrolling shoot'em up. From today's point of view, they may not look too spectacular, but back in 1983 - well, the VC-20 was certainly not leading the competition, but its abilities were good enough for some decent gaming and early applications.
But Commodore had, by that time, already released what would become the best-selling computer ever: the VIC-30 aka C64, which much better capabilities like hardware sprites and improved sound |
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