Commodore 64

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Commodore 64

Type	Home computer
Release date	August 1982
Discontinued	April 1994
Operating system	Commodore KERNAL/ Commodore BASIC 2.0
CPU	MOS Technology 6510 @ 1.023 MHz (NTSC version) @ 0.985 MHz (PAL version)
Memory	64 kB RAM + 20 kB ROM
Graphics	VIC-II (320 × 200, 16 colors, sprites, raster interrupt)
Sound	SID 6581 (3× Osc, 4× Wave, Filter, ADSR, Ring)
Connectivity	2× CIA 6526 Joystick, Power, Cartridge, RF, A/V, IEEE-488 Floppy/Printer, Digital tape, GPIO/RS-232
Predecessor	Commodore VIC-20
Successor	Commodore 128

The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982. Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$ 595^[1][2]. Preceded by the Commodore VIC-20 and Commodore MAX Machine, the C64 features 64 kilobytes (65 536 bytes) of memory with sound and graphics performance that were superior to IBM-compatible computers of that time. It is commonly known as the C64 or C=64 (after the graphic logo on the case) and occasionally as the CBM 64 (for Commodore Business Machines), or VIC-64^[3] It has also been affectionately nicknamed the "breadbox" and "bullnose" due to the shape and color of the first version of its casing^{[citation needed]}.

During the C64's lifetime, sales totaled 30 million units, making it the best-selling single personal computer model of all time.^[4] For a substantial period of time (1983–1986), the C64 dominated the market with between 30% and 40% share and 2 million units sold per year^[5], outselling the IBM PC clones, Apple Inc. computers, and Atari 8-bit family computers. Sam Tramiel, a former Atari president said in a 1989 interview "When I was at Commodore we were building 400,000 C64s a month for a couple of years."^[6]

Part of its success was because it was sold in retail stores instead of electronics stores, and also because these machines can be directly plugged into an existing home television without any modifications. Commodore produced many of its parts in-house to control supplies and cost. It is sometimes compared to the Ford Model-T automobile for bringing a new technology to middle-class households via creative mass-production^[7].

Approximately 10,000 commercial software titles were made for the Commodore 64 including development tools, office applications, and games^[8]. Various C64 emulators allow anyone with a modern computer, or a compatible game console, to run these programs today. The machine is also credited with popularizing the computer demo scene. The C64 is still used today by some computer hobbyists^[9].

Since 28 March 2008, Commodore 64 games have been available to buy through Nintendo's Virtual Console service in Europe; the first games available were Uridium and International Karate^[10][11]. Later, on February 23, 2009, the Commodore 64 section was launched in North America with the first three titles, International Karate, The Last Ninja and Pitstop II. A C64 emulator application with classic games also appears on Apple Inc.'s App Store.

Contents 1 History 1.1 Winning the market war 1.2 The C64 family 1.3 C64 clones 2 Software 2.1 BASIC 2.2 Alternative Operating Systems 3 Hardware 3.1 CPU and memory 3.2 Graphics 3.3 Sound 3.4 Hardware revisions 3.4.1 ICs 3.4.2 Motherboard 3.5 Power supply 3.6 Specifications 3.6.1 Internal hardware 3.6.2 I/O ports and power supply 4 Trivia 5 See also 6 Footnotes 7 References 8 External links

[edit] History

In January 1981, MOS Technology, Inc., Commodore's integrated circuit design subsidiary, initiated a project to design the graphic and audio chips for a next generation video game console. Design work for the chips, named MOS Technology VIC-II (graphics) and MOS Technology SID (audio), was completed in November 1981^[1].

A game console project was then initiated by Commodore that would use the new chips—called the Ultimax or alternatively the Commodore MAX Machine, engineered by Yash Terakura from Commodore Japan. This project was eventually cancelled after just a few machines were manufactured for the Japanese market.

At the same time, Robert "Bob" Russell (system programmer and architect on the VIC-20) and Robert "Bob" Yannes (engineer of the SID) were critical of the current product line-up at Commodore, which was a continuation of the Commodore PET line aimed at business users. With the support of Al Charpentier (engineer of the VIC-II) and Charles Winterble (manager of MOS Technology), they proposed to Commodore CEO Jack Tramiel a true low-cost sequel to the VIC-20. Tramiel dictated that the machine should have 64 kB of RAM. Although 64 KB of DRAM cost over US$ 100 at the time, he knew that DRAM prices were falling, and would drop to an acceptable level before full production was reached. In November, Tramiel set a deadline for the first weekend of January, to coincide with the 1982 Consumer Electronics Show^[1].

The product was codenamed the VIC-40 as the successor to the popular VIC-20. The team that constructed it consisted of Bob Russell, Bob Yannes and David A. Ziembicki. The design, prototypes and some sample software was finished in time for the show, after the team had worked tirelessly over both Thanksgiving and Christmas weekends.

The machine incorporated Commodore BASIC 2.0 in ROM and available immediately at startup.

When the product was to be presented, the VIC-40 product was renamed C64 in order to fit into the current Commodore business products lineup which contained the P128 and the B256, both named by a letter and their respective memory size.

The C64 made an impressive debut at the January 1982 Winter Consumer Electronics Show, as recalled by Production Engineer David A. Ziembicki: "All we saw at our booth were Atari people with their mouths dropping open, saying, 'How can you do that for $595?'" The answer, as it turned out, was vertical integration; thanks to Commodore's ownership of MOS Technology's semiconductor fabrication facilities, each C64 had an estimated production cost of only US$135.

[edit] Winning the market war

The C64 faced a wide range of competing home computers at its introduction in August 1982. With an impressive price coupled with the C64's more flexible hardware, it quickly out-sold many of its competitors. In the United States the greatest competitors to the C64 were the Atari 8-bit 400 and 800, and the Apple II. The Atari 400 and 800 were very similar in hardware terms, but used custom chips for graphics and sound, and so were very expensive to build^{[citation needed]}. The Apple IIe, the latest in the aging Apple II line had higher resolution graphics modes than the C64^[12][13], but due to poor color support they were rarely used^{[citation needed]}, so in practice the C64's 16-color (4-bit) graphics and sound abilities outmatched them at the time of its release. Upgrade capability for the Apple II was granted by internal expansion slots, while C64 had only an external cartridge plug. The C64 had most of the capabilities of some common Apple II expansion cards built-in, however^{[citation needed]}.

All four machines had similar standard memory configurations in the years 1982/83: 48 kB for the Apple II+^[14] (upgraded within months of C64's release to 64K with the Apple IIe) and 48K for the Atari 800^[15]. At upwards of US$ 1200^[16], the Apple II was more than twice as expensive, while the Atari 800 cost US$899. One key to the C64's success was Commodore's aggressive marketing tactics, and they were quick to exploit the relative price/performance divisions between its competitors with a series of television commercials after the C64's launch in late 1982^[17].

Commodore sold the C64 not only through its network of authorized dealers, but also placed it on the shelves of department stores, discount stores, and toy stores. The C64 had a built-in RF modulator and thus could be plugged into a television set. This allowed it (like its predecessor, the VIC-20) to compete directly against video game consoles such as the Atari 2600. Like the Apple IIe, the C64 could also output composite video and thus could be plugged into a specialized monitor for a sharper picture.

Aggressive pricing of the C64 is considered to be a major catalyst in the North American video game crash of 1983. In January 1983, Commodore offered a US$ 100 rebate in the United States on the purchase of a C64 to anyone trading in another computer or video game console. To take advantage of this rebate, some mail-order dealers and retailers offered a Timex Sinclair 1000 for as little as US$ 10 with purchase of a C64, so the consumer could send the TS1000 to Commodore, collect the rebate, and pocket the difference; Timex Corporation departed the marketplace within a year. This soon led to a price war with the major home computer manufacturers. The success of the VIC-20 and C64 contributed significantly to the exit of Texas Instruments and other smaller competitors from the field. The price war with Texas Instruments (TI) was seen as a personal battle for Commodore president Jack Tramiel; TI's subsequent demise in the home computer industry in October 1983 was seen as revenge for TI's tactics in the electronic calculator market in the mid 1970s, when Commodore was almost bankrupted by TI^[18]. In parts of the US in the late 1980s, new C64s could be purchased in retail chains for a little more than US$ 100.

In 1984, Commodore released the Commodore Plus/4. The Plus/4 offered a higher-color display, a better implementation of BASIC (V3.5), and built-in software. However, Commodore committed what was perceived by critics and consumers as a major strategic error by making it incompatible with the C64. The Plus/4 lacked hardware sprite capability and had much poorer sound, thus seriously under performing in two of the areas that had made the C64 a star.

In Europe, the primary competitors to the C64 were the British-built Sinclair ZX Spectrum, BBC Microcomputer and the Amstrad CPC 464. In the UK, the Spectrum had been released a few months ahead of the C64, and was selling for less than half the price. The Spectrum quickly became the market leader and Commodore had an uphill struggle against the Spectrum as it could not rely on undercutting the competition. The C64 debuted at £399 in early 1983, while the Spectrum cost £175. The C64 would later rival the Spectrum in popularity in the latter half of the 1980s, eventually outliving the Spectrum when it was discontinued in December 1990.

Despite a few attempts by Commodore to discontinue the C64 in favor of other, higher priced machines, constant demand made its discontinuation a hard task. By 1988, Commodore was selling 1.5 million C64s worldwide^[19]. Although demand for the C64 dropped off in the US by 1990, it continued to be popular in the UK and other European countries. In the end, economics, not obsolescence, sealed the C64's fate. In March 1994, at CeBIT in Hanover, Germany, Commodore announced that the C64 would be finally discontinued in 1995. Commodore claimed that the C64's disk drive was more expensive to manufacture than the C64 itself. Although Commodore had planned to discontinue the C64 by 1995, the company filed for bankruptcy a month later, in April 1994^[20].

[edit] The C64 family

1982: Commodore released the Commodore MAX Machine in Japan. It is called the Ultimax in the US, and VC-10 in Germany. The MAX was intended to be a game console with limited computing capability, and was based on a very cut-down version of the hardware family later used in the C64. The MAX was discontinued months after its introduction, because of poor sales in Japan.

1983 saw Commodore attempt to compete with the Apple II's hold on the U.S. education market with the Educator 64^[21], essentially a C64 and monochrome monitor in a PET case. Schools preferred the all-in-one metal construction of the PET over the standard C64's separate components, which could be easily damaged, vandalized or stolen.

In 1984, Commodore released the SX-64, a portable version of the C64. The SX-64 has the distinction of being the first full-color portable computer. The base unit featured a 5 in (130 mm) CRT and an integrated 1541 floppy disk drive. The SX-64 did not have a cassette connector.

Commodore was determined to avoid the problems of the Plus/4, making sure that the eventual successors to the C64—the Commodore 128 and 128D computers (1985)—were as good as, and fully compatible with the original, as well as offering a host of improvements (such as a structured BASIC with graphics and sound commands, 80-column display capability, and full CP/M compatibility).

In 1986, Commodore released the Commodore 64C (C64C) computer, which was functionally identical to the original, but whose exterior design was remodeled in the sleeker style of the Commodore 128 and other contemporary design trends. The modifications to the C64 line were more than skin deep in the C64C with new versions of the SID, VIC and I/O chips being deployed—with the core voltage reduced from 12v to 9v. In the United States, the C64C was often bundled with the third-party GEOS GUI-based operating system. The Commodore 1541 disk drive received a matching face-lift resulting in the 1541c. Later a smaller, sleeker 1541-II model was introduced along with the 800 KB 3.5-inch capable 1581.

In 1990, the C64 was re-released in the form of a game console, called the C64 Games System (C64GS). A simple modification to the C64C's motherboard was made to orient the cartridge connector to a vertical position. This allowed cartridges to be inserted from above. A modified ROM replaced the BASIC interpreter with a boot screen to inform the user to insert a cartridge. The C64GS was another commercial failure for Commodore, and it was never released outside of Europe.

In 1990, an advanced successor to the C64, the Commodore 65 (also known as the "C64DX"), was prototyped, but the project was canceled by Commodore's chairman Irving Gould in 1991. The C65's specifications were very good for an 8-bit computer. For example, it could display 256 colors on screen, while OCS based Amigas could only display 64 in HalfBrite mode (32 colors and half-bright transformations); the HAM mode on the Amiga allowed all 4096 colors of the 12 bit color system, but it was awkward to use and had restrictions on color combinations between adjacent pixels. Although no specific reason was given for the C65's cancellation, it would have competed in the marketplace with Commodore's lower end Amigas.

[edit] C64 clones

In the middle of 2004, after an absence from the marketplace of more than 10 years, PC manufacturer Tulip Computers BV (owners of the Commodore brand since 1997) announced the C64 Direct-to-TV (C64DTV), a joystick-based TV game based on the C64 with 30 games built into ROM. Designed by Jeri Ellsworth, a self-taught computer designer who had earlier designed the modern C-One C64 implementation, the C64DTV was similar in concept to other mini-consoles based on the Atari 2600 and Intellivision which had gained modest success earlier in the decade. The product was advertised on QVC in the United States for the 2004 holiday season. Some users have installed 1541 floppy disk drives, hard drives, second joysticks and keyboards to these units, which give the DTV devices nearly all of the capabilities of a full Commodore 64. The DTV hardware is also used in the mini-console/game Hummer, sold at RadioShack mid-2005.

C64 enthusiasts still develop new hardware, including Ethernet cards^[22], specially adapted hard disks and Flash Card interfaces.

[edit] Software

At the time of its introduction, the C64's graphics and sound capabilities were rivalled only by the Atari 8-bit family. This was at a time when most IBM PCs and compatibles had text-only display adapter cards, monochrome monitors, and sound consisting of squeaks and beeps from the built-in tiny, low-quality speaker.

The C64 is often credited with starting the computer subculture known as the demoscene (see Commodore 64 demos). The C64 lost its top position among demo coders when the 16-bit Commodore Amiga and Atari ST were released in 1985, however it still remained a very popular platform for demo coding up to the early 90s^{[citation needed]}.

It is still being actively used as a demo machine^[23], especially for music (its sound chip even being used in special sound cards for PCs, and the Elektron SidStation synthesizer). Unfortunately, the differences between PAL and NTSC C64s caused compatibility problems between U.S./Canadian C64s and those from most other countries. The vast majority of demos run only on PAL machines.

Having been released in 1982, the C64 was still a strong competitor to the Nintendo Entertainment System and Sega Master System, released in the following years, thanks to its by-then established software base. During the 1980s, the Commodore 64 was also used to run numerous Bulletin Board Systems using highly optimized Blue Board software.

[edit] BASIC

As was common for machines of the time, the C64 incorporated a ROM based version of the BASIC programming language. Commodore BASIC 2.0 was used instead of the more advanced BASIC 4.0 from the PET series, since the C64 was intended to be a lower end home computer, and its users were not expected to utilize the disk-oriented enhancements of BASIC 4.0. "The choice of BASIC 2.0 instead of 4.0 was made with some soul-searching, not just at random. The typical user of a C64 is not expected to need the direct disk commands as much as other extensions, and the amount of memory to be committed to BASIC was to be limited. We chose to leave expansion space for color and sound extensions instead of the disk features. As a result, you will have to handle the disk in the more cumbersome manner of the 'old days'."^[24]

The version of BASIC was limited and didn't include commands for sound or graphics manipulation, instead users had to use the "poke" command to access the graphics and sound chip registers directly. Commodore produced a cartridge-based extension to BASIC 2.0 — Simons' BASIC this added many additional commands for graphics and sound.

[edit] Alternative Operating Systems

A number of third party operating systems have been developed for the C64.

As well as the original GEOS, two third-party GEOS-compatible operating systems have been written: Wheels and GEOS megapatch. Both of these require hardware upgrades to the original C64.

Several other operating systems are or have been available, including WiNGS OS, the Unix-like LUnix, operated from a command-line, and the embedded systems OS Contiki, with full GUI. Other less well known OSes include ACE, Asterix, DOS/65 and GeckOS.

A version of CP/M was released, but this required the addition of an external Z80 processor to the expansion bus, so is not considered a true C64 OS. Furthermore, the Z80 processor was underclocked to be compatible with the C64's memory bus, so performance was poor compared to other CP/M implementations. C64 CP/M and C128 CP/M both suffered a lack of software: although most commercial CP/M software would technically run on these systems, software media was incompatible between platforms. The low uptake of CP/M on Commodores meant that software houses saw no need to invest in mastering versions for the Commodore filesystem.

[edit] Hardware

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[edit] CPU and memory

The C64 uses an 8-bit MOS Technology 6510 microprocessor. This is a close derivative of the 6502, with an added 6-bit internal I/O port that in the C64 is used for two purposes: to bank-switch the machine's ROM in and out of the processor's address space, and to operate the datasette tape recorder.

The C64 has 64 KB of RAM, of which 38 kB are available to built-in Commodore BASIC 2.0.

[edit] Graphics

The graphics chip, VIC-II, features 16 colors, eight hardware sprites per scanline (enabling up to 112 sprites per PAL screen), scrolling capabilities, and two bitmap graphics modes. The standard text mode features 40 columns, like most Commodore PET models; the built in character encoding is not standard ASCII but PETSCII, an extended form of ASCII-1963.

Most screen shots show borders around the screen, which is a feature of the VIC-II chip. By utilising interrupts to reset various hardware registers on precise timings it was possible to place graphics within the borders and thus utilise the full screen.^[25]

[edit] Sound

The sound chip, SID, has three channels, each with its own ADSR envelope generator, ring modulation and filter capabilities. It was designed by Bob Yannes, who would later co-found synthesizer company Ensoniq. Yannes criticized other contemporary computer sound chips as "primitive, obviously... designed by people who knew nothing about music". Often the game music became a hit of its own among C64 users. Well-known composers and programmers of game music on the C64 are Rob Hubbard, David Whittaker, Chris Hülsbeck, Ben Daglish, Martin Galway and David Dunn among many others. Due to the chip's limitation to three channels, chords are played as arpeggios typically, coining the C64's characteristic lively sound. It was also possible to continuously update the master volume with sampled data to enable the playback of 4-bit digitized audio.

There are two versions of the SID chip, the 6581 and the 8580. The MOS Technology 6581 was used in all of the original "breadbox" C64s, the early versions of the C64C and the Commodore 128. The 6581 was replaced with the MOS Technology 8580 in 1987. The 6581 sound quality is a little more crisp, and many Commodore 64 fans prefer its sound. The main difference between the 6581 and the 8580 is the supply voltage. The 6581 uses a 12 volt supply, the 8580, a nine volt supply. A modification can be made to use the 6581 in a C64C board (which uses the nine volt chip).

The SID chip has a distinctive sound which retained a following of devotees to such a degree, that a number of audio enthusiasts and companies have designed SID-based products as add-ons for the C64, x86 PCs, and standalone or MIDI music devices such as the Elektron SidStation. These devices use chips taken from excess stock, or removed from used computers.

In 2007, Timbaland's extensive use of the SidStation led to the 2007 Timbaland plagiarism controversy around his tracks Block Party and Do It (written for Nelly Furtado).

[edit] Hardware revisions

Cost reduction was the driving force behind the C64's motherboard revisions. Reducing manufacturing costs was vitally important to Commodore's survival during the price war and leaner years of the 16-bit era. The C64's original (NMOS based) motherboard would go through two major redesigns, (and numerous sub-revisions) exchanging positions of the VIC-II, SID and PLA chips. Initially, a large portion of the cost was eliminated by reducing the number of discrete components, such as diodes and resistors, which enabled the use of a smaller printed circuit board.

[edit] ICs

The VIC-II was manufactured with 5 micrometer NMOS technology^[1] and was clocked at either 17.73447 MHz (PAL) or 14.31818 MHz (NTSC). Internally, the clock was divided down to generate the dot clock (about 8 MHz) and the two-phase system clocks (about 1 MHz; the exact pixel and system clock speeds are slightly different between NTSC and PAL machines). At such high clock rates, the chip generated a lot of heat, forcing MOS Technology to use a ceramic DIL package (called a "CERDIP"). The ceramic package was more expensive, but it dissipated heat more effectively than plastic.

After a redesign in 1983, the VIC-II was encased in a plastic Dual Inline Package, which reduced costs substantially, but it did not totally eliminate the heat problem^[1]. Without a ceramic package, the VIC-II required the use of a heat sink. To avoid extra cost, the metal RF shielding doubled as the heat sink for the VIC, although not all units shipped with this type of shielding. Most C64s in Europe shipped with a cardboard RF shield, coated with a layer of metal foil. The effectiveness of the cardboard was highly questionable, and worse still it acted as an insulator, blocking airflow which trapped heat generated by the SID, VIC, and PLA chips.

The SID was manufactured using NMOS at 7 and in some areas 6 micrometers^[1]. The prototype SID and some very early production models featured a ceramic Dual Inline Package, but unlike the VIC-II, these are extremely rare as the SID was encased in plastic when production started in early 1982.

[edit] Motherboard

In 1986, Commodore released the last revision to the classic C64 motherboard. It was otherwise identical to the 1984 design, except for the two 64 kilobit × 4 bit DRAM chips that replaced the original eight 64 kilobit × 1 bit ICs.

After the release of the C64C, MOS Technology began to reconfigure the C64's chipset to use HMOS production technology. The main benefit of using HMOS was that it required less voltage to drive the IC, which consequently generates less heat. This enhanced the overall reliability of the SID and VIC-II. The new chipset was re-numbered to 85xx in order to reflect the change to HMOS.

In 1987 Commodore released C64Cs with a totally redesigned motherboard commonly known as a "short board". The new board used the new HMOS chipset, featuring a new 64-pin PLA chip. The new "SuperPLA", as it was dubbed, integrated many discrete components and TTL chips. In the last revision of the C64C motherboard, the 2114 color RAM was integrated into the SuperPLA.

[edit] Power supply

The C64 used an external power supply. This saved space within the computer's case. The 1541-II and 1581 disk drives, along with various third-party clones, also came with their own external power supply "bricks".

[edit] Specifications

[edit] Internal hardware

• Microprocessor CPU:
  • MOS Technology 6510/8500 (the 6510/8500 being a modified 6502 with an integrated 6-bit I/O port)
  • Clock speed: 0.985 MHz (PAL) or 1.023 MHz (NTSC)
• Video: MOS Technology VIC-II 6567/8562 (NTSC), 6569/8565 (PAL)
  • 16 colors
  • Text mode: 40×25 characters; 256 user-defined chars (8×8 pixels, or 4×8 in multicolor mode); 4-bit color RAM defines foreground color
  • Bitmap modes: 320×200 (2 unique colors in each 8×8 pixel block)^[26], 160×200 (3 unique colors + 1 common color in each 4×8 block)^[27]
  • 8 hardware sprites of 24×21 pixels (12×21 in multicolor mode)
  • Smooth scrolling, raster interrupts
• Sound: MOS Technology 6581/8580 SID
  • 3-channel synthesizer with programmable ADSR envelope
  • 8 octaves
  • 4 waveforms: Triangle, Sawtooth, Variable pulse, Noise
  • Oscillator synchronization, ring modulation
  • Programmable filter: high pass, low pass, band pass, notch filter
• Input/Output: Two 6526 Complex Interface Adapters
  • 16 bit parallel I/O
  • 8 bit serial I/O
  • Time of Day clock (TOD)
  • 16 bit cascadable timers
• RAM:
  • 64 kB, of which 38 kB (minus 1 byte) were available for BASIC programs
  • 512 bytes color RAM
  • Expandable to 320 kB with Commodore 1764 256 kB RAM Expansion Unit (REU); although only 64 kB directly accessible; REU mostly intended for GEOS. REUs of 128 kB and 512 kB, originally designed for the C128, were also available, but required the user to buy a stronger power supply from some third party supplier; with the 1764 this was included. Creative Micro Designs also produced a 2 MB REU for the C64 and C128, called the 1750 XL. The technology actually supported up to 16 MB, but 2 MB was the biggest one officially made. Expansions of up to 16 MB were also possible via the CMD SuperCPU.
• ROM:
  • 20 kB (9 kB BASIC 2.0; 7 kB KERNAL; 4 kB character generator, providing two 2 kB character sets)

[edit] I/O ports and power supply

• I/O ports:^[28]
  • Cartridge expansion slot (slot for edge connector with 6510 CPU address/data bus lines and control signals, as well as GND and voltage pins; used for program modules and memory expansions, among others)
  • Integrated RF modulator antenna output via a RCA connector. The used channel could be adjusted from number 36 with the potentiometer to the left.
  • 8-pin DIN connector containing composite video output, separate Y/C outputs and sound input/output. Beware that this is the 270° (horseshoe) version of the plug, not the 360° circular version. Also note that some early C64 units use a 5-pin DIN connector that carries composite video and luminance signals, but lacks a chroma signal.^[29]
  • Serial bus (serial version of IEEE-488, 6-pin DIN plug) for CBM printers and disk drives
  • PET-type Commodore Datassette 300 baud tape interface (edge connector with digital cassette motor/read/write/sense signals, Ground and +5V lines. The tape drive motor is powered directly from the 5V line)
  • User port (edge connector with TTL-level signals, for modems etc.; byte-parallel signals which can be used to drive third-party parallel printers, among other things, 17 logic signals, 7 Ground and voltage pins, including 9V AC)
  • 2 × screwless DE9M game controller ports (compatible with Atari 2600 controllers), each supporting five digital inputs and two analog inputs. Available peripherals included digital joysticks, analog paddles, a light pen, the Commodore 1351 mouse, and the unique KoalaPad.

• Power supply:
  • 5V DC and 9VAC from an external "power brick", attached to a 7-pin female DIN-connector on the computer^[30].

The 9 volt AC is used to supply power via a charge pump to the SID sound generator chip, provide 6.8V via a rectifier to the cassette motor, a "0" pulse for every positive half wave to the time-of-day (TOD) input on the CIA chips, and 9 volts AC directly to the user-port. Thus, as a minimum, a 12 V square wave is required. But a 9 V sine wave is preferred^[31][32].

[edit] Trivia

Lists of miscellaneous information should be avoided. Please relocate any relevant information into appropriate sections or articles. (April 2010)

• On address $FFF6-$FFF9 (65526-9) in the C64 KERNAL, immediately before the hard-coded jump vectors for the processor, is letter sequence "RRBY". These are the initials of Robert Russell and Robert Yannes (Bob Yannes), the two main engineers that created the C64.
• Due to a quirk in the C64's BASIC operating system, an unintentional Easter egg or "screensaver" of sorts may be activated by first holding the RUN/STOP key, tapping the RESTORE key, then entering POKE781,96:SYS58251 on the subsequently cleared screen.
• There are ways to hide lines of code written in the BASIC Language stored in local memory, using control characters outside delimiting quotes, which the BASIC LIST function displayed as cursor control codes. For example, the reverse "heart" symbol () would clear the screen, the reverse [ character would delete characters, and the character shift-L (which looks like an L-shaped border corner) in the program code would cause a syntax error and abort the LISTing.
• Using short commands (usually the first letter, then shift and the second) it was possible to make BASIC lines more than two display rows long. The C64 could not parse more than two display rows when the subsequent code was LISTed, so lines constructed in this fashion could not be edited — to make changes to them, the user would have to re-type the entire line.
• As with all Commodore machines running BASIC, typing 350800 and hitting Enter leads to unpredictable results due to a bug in the BASIC interpreter.

[edit] See also

• Commodore SX-64 – Portable version
• Commodore 64 peripherals
• List of Commodore 64 games
• Commodore 64 demos
• Commodore MAX Machine – the Commodore 64's predecessor
• Commodore 128 – the Commodore 64's descendant
• 1541 Ultimate – System state controller & storage peripheral.
• C-One – Programmable FPGA clone
• C64 Direct-to-TV – ASIC clone with 30 built in games
• IDE64 – P-ATA interface cartridge for the C64

[edit] Footnotes

[edit] References

[edit] External links

Wikimedia Commons has media related to: Commodore 64

• Commodore 64 at the Open Directory Project
• Chronology of the Commodore 64 Computer
• The History of the Commodore 64
• Commodore 64 history, manuals, and photos
• Extensive collection of information on C64 programming
• A History of Gaming Platforms: The Commodore 64 from October 2007
• Images of the C64 prototype from 2003
• A Commodore 64 Web Server Using Contiki v2.3
• Commodore 8-bit web links Project 70 sites and counting
• "Commodore 64 still loved after all these years", CNN
• "The Commodore 64 at 25: thank you for the music", The Guardian
• "How to use the Commodore 64 for chiptunes", 2D-X

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