The

MOS Technology MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a semiconductor design and fabrication company based in Audubon, Pennsylvania. It is mos ...

6581/8580 SID (Sound Interface Device) is the built-in programmable sound generator chip of

Commodore Commodore may refer to: Ranks * Commodore (rank), a naval rank ** Commodore (Royal Navy), in the United Kingdom ** Commodore (United States) ** Commodore (Canada) ** Commodore (Finland) ** Commodore (Germany) or ''Kommodore'' * Air commodore ...

's CBM-II,

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...

Commodore 128 The Commodore 128, also known as the C128, C-128, C= 128,The "C=" represents the graphical part of the logo. is the last 8-bit home computer that was commercially released by Commodore Business Machines (CBM). Introduced in January 1985 at the ...

and Commodore MAX Machine home computers. It was one of the first sound chips of its kind to be included in a home computer prior to the

digital sound revolution The digital sound revolution (or digital audio revolution) refers to the widespread adoption of digital audio technology in the computer industry beginning in the 1980s. Prior methods Software-based pulse-width modulation Some of the first c ...

. Together with the

VIC-II The VIC-II (Video Interface Chip II), specifically known as the MOS Technology 6567/8562/8564 (NTSC versions), 6569/8565/8566 ( PAL), is the microchip tasked with generating Y/C video signals (combined to composite video in the RF modulator) and ...

graphics chip, the SID was instrumental in making the C64 the best-selling home computer in history, and is partly credited for initiating the

demoscene The demoscene is an international computer art subculture focused on producing demos: self-contained, sometimes extremely small, computer programs that produce audiovisual presentations. The purpose of a demo is to show off programming, visual ...

Design process

The SID was devised by engineer Robert "Bob" Yannes, who later co-founded the Ensoniq digital

synthesizer A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and ...

and sampler company. Yannes headed a team that included himself, two technicians and a

CAD Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...

operator, who designed and completed the chip in five months in the latter half of 1981. Yannes was inspired by previous work in the synthesizer industry and was not impressed by the current state of computer sound chips. Instead, he wanted a high-quality instrument chip, which is the reason why the SID has features like the

envelope generator In sound and music, an envelope describes how a sound changes over time. It may relate to elements such as amplitude (volume), frequencies (with the use of filters) or pitch. For example, a piano key, when struck and held, creates a near-im ...

, previously not found in home computer sound chips. Emphasis during chip design was on high-precision frequency control, and the SID was originally designed to have 32 independent voices, sharing a common wavetable lookup scheme that would be time multiplexed. However, these features could not be finished in time, so instead the mask work for a certain working oscillator was simply replicated three times across the chip's surface, creating three voices each with its own oscillator. Another feature that was not incorporated in the final design was a frequency look-up table for the most common musical notes, a feature that was dropped because of space limitations. The support for an audio input pin was a feature Yannes added without asking, which in theory would have allowed the chip to be used as a simple effect processor. The masks were produced in 7-micrometer technology to gain a high yield; the state of the art at the time was 6-micrometer technologies. The chip, like the first product using it (the Commodore 64), was finished in time for the Consumer Electronics Show in the first weekend of January 1982. Even though Yannes was partly displeased with the result, his colleague Charles Winterble said: "This thing is already 10 times better than anything out there and 20 times better than it needs to be." The specifications for the chip were not used as a blueprint. Rather, they were written as the development work progressed, and not all planned features made it into the final product. Yannes claims he had a feature-list of which three quarters made it into the final design. The later revision (8580) was revised to more closely match the specifications. For example, the 8580 slightly improved upon the ability to perform a binary AND between two waveforms, which the SID can only do in an odd and illogical manner that results in messy, and in some cases nearly silent, waveforms. Wave combinations on the 8580 result in cleaner waveforms than on the 6581, although irregularities are still present. Another feature that differs between the two revisions is the filter, as the 6581 version is far away from the specification.

Manufacturing, remarking, and forgery

Since 6581 and 8580 SID ICs are no longer produced, they have become highly sought after. In late 2007, various defective chips started appearing on eBay as supposedly "new". Some of these remarked SIDs have a defective filter, but some also have defective channels/noise generators, and some are completely dead. The remarked chips are assumed to either be factory rejects from back when the chip was still produced, or possibly "reject pulls" from one of the chip pulling operations that were used to supply the chips used in the

HardSID {{Unreferenced, date=November 2020 The HardSID is a family of sound cards, produced by a Hungarian company Hard Software and originally conceived by Téli Sándor. The HardSID cards are based on the MOS Technology SID (Sound Interface Device) ch ...

cards. Fake SID chips have also been supplied to unwitting buyers from unscrupulous manufacturers in China; the supplied chips are laser-etched with completely bogus markings, and the chip inside the package is not a SID at all.

Features

* Three separately programmable independent audio oscillators (8

octave In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...

range, approximately 16 - 4000 Hz) * Four different

waveform In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.David Crecraft, David Gorham, ''Electro ...

s per audio oscillator ( sawtooth,

triangle A triangle is a polygon with three Edge (geometry), edges and three Vertex (geometry), vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, an ...

pulse In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the n ...

noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...

) * One multi mode

filter Filter, filtering or filters may refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Filter (software), a computer program to process a data stream * Filter (video), a software component tha ...

featuring

low-pass A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filte ...

high-pass A high-pass filter (HPF) is an electronic filter that passes signals with a frequency higher than a certain cutoff frequency and attenuates signals with frequencies lower than the cutoff frequency. The amount of attenuation for each frequency d ...

and

band-pass A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range. Description In electronics and signal processing, a filter is usually a two-po ...

outputs with 6 dB/oct (bandpass) or 12 dB/

(lowpass/highpass)

rolloff Roll-off is the steepness of a transfer function with frequency, particularly in electrical network analysis, and most especially in connection with filter circuits in the transition between a passband and a stopband. It is most typically app ...

. The different filter modes are sometimes combined to produce additional timbres, for instance a notch-reject filter. * Three attack/decay/sustain/release ( ADSR) volume controls, one for each audio oscillator * Three ring modulators *

Oscillator sync Oscillator sync is a feature in some synthesizers with two or more VCOs, DCOs, or "virtual" oscillators. As one oscillator finishes a cycle, it resets the period of another oscillator, forcing the latter to have the same base frequency. This can ...

for each audio oscillator * Two 8-bit

analog-to-digital converter In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide ...

s (typically used for game control

paddles A paddle is a handheld tool with an elongated handle and a flat, widened distal end (i.e. the ''blade''), used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered w ...

, but later also used for a

mouse A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

) * External audio input (for sound mixing with external signal sources) *

Random number In mathematics and statistics, a random number is either Pseudo-random or a number generated for, or part of, a set exhibiting statistical randomness. Algorithms and implementations A 1964-developed algorithm is popularly known as ''the Knuth s ...

/modulation generator

Technical details

The SID is a

mixed-signal integrated circuit A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die.variable duty cycle), triangle wave, sawtooth wave, pseudorandom noise (called

white noise In signal processing, white noise is a random signal having equal intensity at different frequencies, giving it a constant power spectral density. The term is used, with this or similar meanings, in many scientific and technical disciplines, ...

in documentation), and certain complex/combined waveforms when multiple waveforms are selected simultaneously. The oscillators of each voice are built off of a 24-bit

phase accumulator A numerically-controlled oscillator (NCO) is a digital signal generator which creates a synchronous (i.e. clocked), discrete-time, discrete-valued representation of a waveform, usually sinusoidal. NCOs are often used in conjunction with a digital- ...

. A voice playing a triangle waveform may be ring-modulated with one of the other voices, where the triangle waveform's bits are inverted when the MSB of the modulating voice's accumulator is set, producing a discontinuity and inversion of direction with the triangle's ramp. Voices may also be hard-synced to each other, where the synced voice's oscillator is reset whenever the MSB of the syncing voice's accumulator is increased. If both ring modulation and hard-sync are set to affect the same voice, the two effects are combined. The voice that ring modulates and/or syncs a given affected voice is determined by the following pattern: voice 1 affects voice 2, voice 2 affects voice 3, and voice 3 affects voice 1. Each voice may be routed into a common, digitally controlled analog multimode filter, which is constructed with aid of external capacitors to the chip. The filter has lowpass, bandpass and highpass outputs, which can be individually selected for final output amplification via the master volume register. Filter modes can also be combined together. For example, using a combined state of lowpass and highpass results in a notch (or inverted bandpass) output. The programmer may vary the filter's cutoff frequency and resonance. An external audio-in port enables external audio to be passed through the filter. The ring modulation, filter, and programming techniques such as arpeggio (rapid cycling between frequencies to make chord-like sounds) together produce the characteristic feel and sound of SID music. Due to imperfect manufacturing technologies of the time and poor separation between the analog and digital parts of the chip, the 6581's output (before the amplifier stage) was always slightly biased from the zero level. Each time the volume register was altered, an audible click was produced. By quickly adjusting the amplifier's gain through the main 4-bit volume register, this bias could be modulated as PCM, resulting in a "virtual" fourth channel allowing 4-bit digital sample playback. The glitch was known and used from an early point on, first by Electronic Speech Systems to produce sampled speech in games such as ''

Impossible Mission ''Impossible Mission'' is a video game originally written for the Commodore 64 by Dennis Caswell and published by Epyx in 1984. The game features a variety of gameplay mechanics from platform and adventure games, and includes digitized speech. ...

'' (1983, Epyx) and ''

Ghostbusters ''Ghostbusters'' is a 1984 American supernatural comedy film directed and produced by Ivan Reitman, and written by Dan Aykroyd and Harold Ramis. It stars Bill Murray, Aykroyd, and Ramis as Peter Venkman, Ray Stantz, and Egon Spengler, thr ...

'' (1984, Activision). The first instance of samples being used in actual musical compositions was by

Martin Galway Martin Galway (born 3 January 1966, Belfast, Northern Ireland) is one of the best known composers of chiptune video game music for the Commodore 64 and the ZX Spectrum. His works include '' Rambo: First Blood Part II'', '' Comic Bakery'' and ...

in ''

Arkanoid is a 1986 block breaker arcade game developed and published by Taito. In North America, it was published by Romstar. Controlling a paddle-like craft known as the Vaus, the player is tasked with clearing a formation of colorful blocks by deflect ...

'' (1987, Imagine), although he had copied the idea from an earlier drum synthesizer package called Digidrums. The length of sampled sound playback was limited first by memory and later technique. Kung Fu Fighting (1986), a popular early sample, has a playback length measured in seconds. c64mp3 (2010) and Cubase64 (2010) demonstrate playback lengths measured in minutes. Also, it was hugely CPU intensive - one had to output the samples very fast (in comparison to the speed of the

6510 300px, Image of the internals of a Commodore 64 showing the 6510 CPU (40-pin DIP, lower left). The chip on the right is the 6581 SID. The production week/year (WWYY) of each chip is given below its name. The MOS Technology 6510 is an 8-bit mic ...

CPU). The better manufacturing technology in the 8580 used in the later revisions of Commodore 64C and the Commodore 128 DCR caused the bias to almost entirely disappear, causing the digitized sound samples to become very quiet. Fortunately, the volume level could be mostly restored with either a hardware modification (biasing the audio-in pin), or more commonly a software trick involving using the Pulse waveform to intentionally recreate the required bias. The software trick generally renders one voice temporarily unusable, although clever musical compositions can make this problem less noticeable. An excellent example of this quality improvement noticeably reducing a sampled channel can be found in the introduction to Electronic Arts' game Skate or Die (1987). The guitar riff played is all but missing when played on the Commodore 64c or the Commodore 128. At the X'2008 demo party, a completely new method of playing digitized samples was unveiled. The method allows for an unprecedented four (software-mixed) channels of 8-bit samples with optional filtering on top of all samples, as well as two ordinary SID sound channels. The method works by resetting the oscillator using the waveform generator test bit, quickly ramping up the new waveform with the Triangle waveform selected, and then disabling all waveforms, resulting in the DAC continuing to output the last value---which is the desired sample. This continues for as long as two scanlines, which is ample time for glitch-free, arbitrary sample output. It is however more CPU-intensive than the 4-bit volume register DAC trick described above. Because the filtering in a SID chip is applied after the waveform generators, samples produced this way can be filtered normally. The original manual for the SID mentions that if several waveforms are enabled at the same time, the result will be a binary AND between them. What happens in reality is that the input to the waveform DAC pins receives several waveforms at once. For instance, the Triangle waveform is made with a separate XOR circuit and a shift-to-left circuit. The top bit drives whether the XOR circuit inverts the accumulator value seen by the DAC. Thus, enabling triangle and sawtooth simultaneously causes adjacent accumulator bits in the DAC input to mix. (The XOR circuit does not come to play because it is always disabled whenever the sawtooth waveform is selected.) The pulse waveform is built by joining all the DAC bits together via a long strip of polysilicon, connected to the pulse control logic that digitally compares current accumulator value to the pulse width value. Thus, selecting the pulse waveform together with any other waveform causes every bit on the DAC to partially mix, and the loudness of the waveform is affected by the state of the pulse. The noise generator is implemented as a 23-bit-length Fibonacci LFSR (Feedback polynomial: x^22+x^17+1). When using noise waveform simultaneously with any other waveform, the pull-down via waveform selector tends to quickly reduce the XOR shift register to 0 for all bits that are connected to the output DAC. As the zeroes shift in the register when the noise is clocked, and no 1-bits are produced to replace them, a situation can arise where the XOR shift register becomes fully zeroed. Luckily, the situation can be remedied by using the waveform control test bit, which in that condition injects one 1-bit into the XOR shift register. Some musicians are also known to use noise's combined waveforms and test bit to construct unusual sounds. The 6581 and 8580 differ from each other in several ways. The original 6581 was manufactured using the older NMOS process, which used 12V DC to operate. The 6581 is very sensitive to static discharge and if they weren't handled properly the filters would stop working, explaining the reason of the great quantity of dead 6581s in the market. The 8580 was made using the HMOS-II process, which requires less power (9V DC), and therefore makes the IC run cooler. The 8580 is thus far more durable than the 6581. Also, due to more stable waveform generators, the bit-mixing effects are less noticeable and thus the combined waveforms come close to matching the original SID specification (which stated that they will be combined as a binary AND). The filter is also very different between the two models, with the 6581 cutoff range being a relatively straight line on a log scale, while the cutoff range on the 8580 is a straight line on a linear scale, and is close to the designers' actual specifications. Additionally, a better separation between the analog and the digital circuits made the 8580's output less noisy and distorted. The noise in 6xxx-series systems can be reduced by disconnecting the audio-in pin. The consumer version of the 8580 was rebadged the 6582, even though the die on the chip is identical to a stock 8580 chip, including the '8580R5' mark. Dr. Evil Laboratories used it in their SID Symphony expansion cartridge (sold to

Creative Micro Designs Creative Micro Designs (CMD) was founded in 1987 by Doug Cotton and Mark Fellows. It is a computer technology company which originally developed and sold products for the Commodore 64 and C128 8-bit personal computers. After 2001 it sold ...

in 1991), and it was used in a few other places as well, including one PC sound-card. Despite its documented shortcomings, many SID musicians prefer the flawed 6581 chip over the corrected 8580 chip, some even seeing the flaws as actual 'features' that made the SID chip distinct from other sound chips at the time. The main reason for this is that the filter produces strong distortion that is sometimes used to produce simulation of instruments such as a distorted electric guitar. Also, the highpass component of the filter was mixed in 3 dB attenuated compared to the other outputs, making the sound more bassy. In addition to nonlinearities in filter, the D/A circuitry used in the waveform generators produces yet more additional distortion that made its sound richer in character.

Revisions

No instances reading "6581 R1" ever reached the market. In fact, Yannes has stated that " heSID chip came out pretty well the first time, it made sound. Everything we needed for the show was working after the second pass." High-resolution photos of Charles Winterble's prototype C64 show the markings "MOS 6581 2082", the last number being a date code indicating that his prototype SID chip was produced during the 20th week of 1982, which would be within 6 days of May 17, 1982. These are the known revisions of the various SID chips: (date codes are in WWYY w=week y=year format) * 6581 R1 - Prototype, only appeared on the CES machines and development prototypes, has a date code of 4981 to 0882 or so. Has the full 12 bit filter cutoff range. An unknown number were produced, probably between 50 and 100 chips. All are ceramic packages. * 6581 R2 - Will say "6581" only on the package. Filter cutoff range was reduced to 11 bits and the LSB bit disconnected/forced permanently on, but is still on the die. The filter is leaky at some ranges and they tend to run hotter than other sid revisions. Made from 1982 until at least 1983. First 10 weeks or so of chips have ceramic packages (these usually appear on engineering prototypes but a few are on sold machines), the rest have plastic packages. * 6581 R3 - Will say "6581" only, "6581 R3" or "6581 CBM" on the package. Had a minor change to the protection/buffering of the input pins. No changes were made to the filter section. Made from before 1983 until 1986 or so. The 6581R3 since around the week 47 of 1985 made in the Philippines use the HMOS HC-30 degree silicon though the manufacturing process remained NMOS. * 6581 R4 - Will say "6581 R4" on the package. Silicon grade changed to HMOS-II "HC-30" grade, though the manufacturing process for the chip remained NMOS. Produced from 1985 until at least 1990. * 6581 R4 AR - Will say "6581 R4 AR" on the package. Minor adjustment to the silicon grade, no die change from R4. Produced from around 1986 (week 22) until at least the year 1992. * 6582 - Will say "6582" on the package. Typically produced around the year 1986 in Hong Kong. * 6582 A - Will say "6582A" (or "6582 A") on the package. Typically produced around the years 1989, 1990 and 1992 in the Philippines. * 8580 R5 - Will say "8580R5" on the package. Produced from the years 1986 to 1993 in the Philippines, Hong Kong and in the US. Some of these chips are marked "CSG" (Commodore Semiconductor Group) with the Commodore logo, while others are marked "MOS". This includes chips produced during the same week (and thus, receiving the same date code), indicating that at least two different factory lines were in operation during that week. The markings of chips varied by factory, and even by line within a factory, throughout most of the manufacturing run of the chip.

Game audio

The majority of games produced for the Commodore 64 made use of the SID chip, with sounds ranging from simple clicks and beeps to complex musical extravaganzas or even entire digital audio tracks. Due to the technical mastery required to implement music on the chip, and its versatile features compared to other sound chips of the era, composers for the Commodore 64 have described the SID as a musical instrument in its own right. Most software did not use the full capabilities of SID, however, because the incorrect published specifications caused programmers to only use well-documented functionality. Some early software, by contrast, relied on the specifications, resulting in inaudible sound effects. Well known composers of game music for this chip are

, known for many titles, including ''

Wizball ''Wizball'' is a shoot 'em up written by Jon Hare and Chris Yates (who together formed Sensible Software) and released in 1987 originally for the Commodore 64 and later in the year for the ZX Spectrum and Amstrad CPC. Versions for the Amiga and ...

'', and '' Times of Lore'',

Rob Hubbard Rob Hubbard (born 1955 in Kingston upon Hull, England) is a British composer best known for his musical and programming work for microcomputers of the 1980s, such as the Commodore 64. Early life Hubbard first started playing music at age seve ...

, known for titles such as '' ACE 2'', ''

Commando Royal Marines from 40 Commando on patrol in the Sangin">40_Commando.html" ;"title="Royal Marines from 40 Commando">Royal Marines from 40 Commando on patrol in the Sangin area of Afghanistan are pictured A commando is a combatant, or operativ ...

'', ''

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...

'', ''

International Karate ''International Karate'' is a fighting game developed and published by System 3 for the ZX Spectrum in 1985 and ported to various home computers over the following years. In the United States it was published by Epyx in 1986 as ''World Karate ...

'', '' IK+'', and '' Monty on the Run''. Other noteworthies include

Jeroen Tel Jeroen Godfried Tel (born 19 May 1972), also known as WAVE, is a Dutch composer. He is best known for numerous computer game tunes he wrote in the 1980s and early 1990s for the Commodore 64. His most popular compositions appear in the following ...

(''Cybernoid'', ''

Turbo Outrun ''Turbo OutRun'' (ターボアウトラン) is a 1989 arcade racing game released by Sega. A follow-up to 1986's ''Out Run'', it was released as a dedicated game, as well as an upgrade kit for the original ''Out Run'' board. Like its predecessor ...

'', ''Robocop 3'' and ''Myth''), Ben Daglish (''

The Last Ninja ''The Last Ninja'' is an action-adventure game originally developed and published by System 3 in 1987 for the Commodore 64. It was converted to the Apple IIGS, MS-DOS, BBC Micro, and Acorn Electron in 1988, the Apple II in 1989, the Amiga, and ...

'', ''

Jack the Nipper ''Jack the Nipper'' is a video game by Gremlin Graphics released in 1986 for ZX Spectrum, Commodore 64, Amstrad CPC, and MSX. It was followed by a sequel, '' Jack the Nipper II: In Coconut Capers''. Gameplay ''Jack the Nipper'' is a side-view ...

'', ''Firelord'', '' Gauntlet''),

David Dunn David John Ian Dunn (born 27 December 1979) is an English former professional football player and manager; he is now a coach at club Port Vale. Dunn played as an attacking midfielder and spent the majority of his playing career representing ...

(''

Finders Keepers Finders, keepers, sometimes extended as the children's rhyme finders, keepers; losers, weepers, is an English language, English adage with the premise that when something is unowned or abandoned, whoever finds it first can claim it for themself pe ...

'' and ''Flight Path 737''), David Whittaker ('' Speedball'', ''BMX Simulator'', ''

Glider Rider ''Glider Rider'' is an isometric action-adventure game published by Quicksilva in 1986 for the ZX Spectrum, Commodore 64, and Amstrad CPC. The music was composed by David Whittaker. Plot The criminal Abraxas Corporation must be destroyed. A ...

'') and

Chris Hülsbeck Christopher Hülsbeck (born 2 March 1968), known internationally as Chris Huelsbeck, is a German video game music composer. He gained popularity for his work on game soundtracks for '' The Great Giana Sisters'' and the '' Turrican'' series. Care ...

(''

R-Type is a horizontally scrolling shooter arcade video game developed and released by Irem in 1987 and the first game in the ''R-Type'' series. The player controls a star ship, the R-9 "Arrowhead", in its efforts to destroy the Bydo, a powerful ...

'', ''

Turrican ''Turrican'' is a 1990 video game developed by Manfred Trenz. It was developed for the Commodore 64 by Rainbow Arts, and was ported to other systems later. In addition to concept design and character creation, Trenz programmed ''Turrican'' on th ...

'' and ''

The Great Giana Sisters ''The Great Giana Sisters'' is a 1987 platform game developed by German studio Time Warp Productions and published by Rainbow Arts. The scroll screen melody of the game was composed by Chris Huelsbeck and is a popular Commodore 64 soundtrack. Th ...

'').

Emulation

The fact that many enthusiasts prefer the real chip sound over software emulators has led to several recording projects aiming to preserve the authentic sound of the SID chip for modern hardware. The sid.oth4 project has over 380 songs of high quality MP3 available recorded on hardsid hardware and the SOASC= project has the entire High Voltage SID Collection (HVSC) released with 49 (over 35,000 songs) recorded from real Commodore 64s in a high quality

MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio developed largely by the Fraunhofer Society in Germany, with support from other digital scientists in the United States and elsewhere. Origin ...

file. Both projects emphasize the importance of preserving the authentic sound of the SID chip. In 2016, the Unepic Stoned High SID Collection (USHSC) was launched. It is a YouTube channel with over 50,000 SID tunes uploaded as single videos. The USHSC is based on both the SOASC= and HVSC, but also uploads recordings of recent SID music released at the Commodore Scene Database (CSDb) site. The channel features playlists containing roughly 5000 tunes each.

Software emulation

* In 1989 on the Amiga computer, the demo "The 100 Most Remembered C64 Tunes" and later the PlaySID application was released, developed by Per Håkan Sundell and Ron Birk. This was one of the first attempts to emulate the SID in software only, and also introduced the file format for representing songs made on the C64 using the SID chip. This later spawned the creation of similar applications for other platforms as well as the creation of a community of people fascinated by SID music, resulting in ''The High Voltage SID Collection'' which contains over 45,000 SID tunes. A SID file contains the

program code and associated data needed to replay the music on the SID. The SID files have the

MIME Multipurpose Internet Mail Extensions (MIME) is an Internet standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs. Message ...

media type audio/prs.sid. The actual file format of a SID file has had several versions. The older standard is PSID (current version V4). The newer standard, RSID, is intended for music that requires a more complete emulation of the Commodore 64 hardware. The SID file format is not a native format used on the Commodore 64 or 128, but a format specifically created for emulator-assisted music players such as ''PlaySID '', ''Sidplay'' and ''JSidplay2''. However, there are loaders like ''RealSIDPlay'' and converters such as ''PSID64'' that make it possible to play a substantial portion of SID files on original Commodore computers. * SIDPlayer, developed by Christian Bauer and released in 1996 for the BeOS operating system, was the first SID emulator to replicate the filter section of the SID chip using a second-order

Infinite impulse response Infinite impulse response (IIR) is a property applying to many linear time-invariant systems that are distinguished by having an impulse response h(t) which does not become exactly zero past a certain point, but continues indefinitely. This is in ...

filter as an approximation. * In June 1998, a cycle-based SID emulator engine called reSID became available. The all-software emulator, available with

C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

, is licensed under the

GPL The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general u ...

by the author, Dag Lem. In 2008, Antti Lankila significantly improved the filter and distortion simulation in reSID. The improvements were included in

VICE A vice is a practice, behaviour, or habit generally considered immoral, sinful, criminal, rude, taboo, depraved, degrading, deviant or perverted in the associated society. In more minor usage, vice can refer to a fault, a negative character tra ...

version 2.1 as well. * In 2007 the JSidplay2 project was released, a pure Java based SID player developed by Ken Händel.

Hardware reimplementations

* In 2008 the HyperSID project was released. HyperSID is a

VSTi Virtual Studio Technology (VST) is an audio plug-in software interface that integrates software synthesizers and effects units into digital audio workstations. VST and similar technologies use digital signal processing to simulate traditional ...

which acts like a MIDI controller for HyperSID hardware unit (synthesizer based on SID chip) and developed by HyperSynth company.

Hardware implementations using the SID chip

* In 1989 Innovation Computer developed the Innovation Sound Standard, an

IBM PC compatible IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. ...

sound card A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio i ...

with a SID chip and a

game port The game port is a device port that was found on IBM PC compatible and other computer systems throughout the 1980s and 1990s. It was the traditional connector for joystick input, and occasionally MIDI devices, until made obsolete by USB in the ...

MicroProse MicroProse is an American video game publisher and video game developer, developer founded by Bill Stealey, Sid Meier, and Andy Hollis in 1982. It developed and published numerous games, including starting the ''Civilization (series), Civilizatio ...

promised software support for the card, and Commodore BASIC programs that used SID required little conversion to run on

GW-BASIC GW-BASIC is a dialect of the BASIC programming language developed by Microsoft from IBM BASICA. Functionally identical to BASICA, its BASIC interpreter is a fully self-contained executable and does not need the Cassette BASIC ROM found in the ...

. * In 1997, an

electronic musical instrument An electronic musical instrument or electrophone is a musical instrument that produces sound using electronic circuitry. Such an instrument sounds by outputting an electrical, electronic or digital audio signal that ultimately is plugged into ...

utilizing the SID chip as its synthesis engine was released. It is called the

SidStation The Elektron SidStation is a musical synthesizer sound module, built around the MOS Technology SID mixed-mode synthesizer chip originally used in the Commodore 64 home computer. It was produced by the Swedish synthesizer company Elektron, and ...

, built around the 6581 model SID chip (as opposed to the newer 8580), and it's produced by

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

company Elektron. As the SID chip had been discontinued for years, Elektron allegedly bought up almost all of the remaining stock. In 2004, Elektron released the

Monomachine The Elektron Monomachine is a synthesizer and music sequencer by Elektron. The Monomachine was available as SFX-60 model, which is a desktop sound module, and was available as the SFX-6 model, which has a keyboard and a joystick controller. ...

pattern-based

sequencer Sequencer may refer to: Technology * Drum sequencer (controller), an electromechanical system for controlling a sequence of events automatically * DNA sequencer, a machine used to automatically produce a sequence readout from a biological DNA sam ...

with optional keyboard. The Monomachine contains several synthesis engines, including an emulated 6581 oscillator using a

DSP DSP may refer to: Computing * Digital signal processing, the mathematical manipulation of an information signal * Digital signal processor, a microprocessor designed for digital signal processing * Yamaha DSP-1, a proprietary digital signal ...

. * In 1999

, another PC sound card, was released. The card uses from one to four SID chips and allows a PC to utilize the sound capabilities of the chip directly, instead of by emulation via generic sound cards (e.g.

SoundBlaster Sound Blaster is a family of sound cards designed by Singaporean technology company Creative Technology (known in the US as Creative Labs). Sound Blaster sound cards were the de facto standard for consumer audio on the IBM PC compatible system pl ...

). * The Catweasel from

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company

Individual Computers Individual Computers is a German computer hardware company specializing in retrocomputing accessories for the Commodore 64, Amiga, and PC platforms. Individual Computers produced the C-One reconfigurable computer in 2003. The company is owned and ...

, a PCI + Zorro multiformat

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...

controller and digital joystick adapter for PCs, Macs, and

Amiga Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphi ...

s, includes a hardware SID option, i.e. an option to insert one or two real SID chips in a socket for use when playing .MUS files. * The MIDIbox SID is a

MIDI MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...

-controlled synthesizer which can contain up to eight SID chips. It is a free

open source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

project using a

PIC microcontroller PIC (usually pronounced as ''"pick"'') is a family of microcontrollers made by Microchip Technology, derived from the PIC1650"PICmicro Family Tree", PIC16F Seminar Presentation originally developed by General Instrument's Microelectronics ...

. Control of the synthesizer is realized with software or via a control panel with knobs,

LEDs A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (cor ...

, LCD, etc., which may optionally be mounted on a keyboardless Commodore 64 body. * The Prophet64 is a cartridge for the Commodore 64. It features four separate music applications, mimicking everything from modern sequencers to the Roland 303/909 series. With an optional User Port peripheral, the Prophet64 may synchronized to other equipment using

DIN Sync DIN sync, also called Sync24, is a synchronization interface for electronic musical instruments. It was introduced in the early 1980s by Roland Corporation and has been superseded by MIDI. Definition and history DIN sync was introduced in t ...

standard (SYNC 24). The website now states "Prophet64 has been replaced with the MSSIAH."http://www.prophet64.com * The MSSIAH is a cartridge for the Commodore 64 that replaces the Prophet64. * Artist/hacker Paul Slocum developed the Cynthcart cartridge that enables you to turn your C64 into an analogue synthesizer. Its successor, Cynthcart 2, added MIDI in, out and thru ports. * The Parallel Port SID Interface allows those with very slim budgets to connect the SID chip to a PC. *In 2003 a SID interface (and software to play Commodore 64 tunes) was released for the

Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...

based

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computer supporting both the 6581 and the 8580. * In May 2009 the SID chip was interfaced to the BBC Micro and BBC Master range of computers via the 1 MHz bus allowing music written for the SID chip on the Commodore 64 to be ported and played on the BBC Micro. * In October 2009 thrashbarg's project interfaced an SID chip to an ATmega8 to play MIDI files on a MOS 6581 SID. * In March 2010 STG published the SIDBlaster/USB - an open source, open hardware implementation of the SID that connects to (and is powered by) a USB port, using an FTDI chip for the USB interface and a PIC to interface the SID. * In August 2010 SuperSoniqs published the Playsoniq, a cartridge for MSX computers, with (in addition to other features) a real SID on it, ready to use on any MSX machine. * In May 2015 Gianluca Ghettini developed SidBerry, an open source, open hardware board to interface a MOS 6581 SID chip to a RaspberryPi and play standard SID music files * In 2016 Thibaut Varene published exSID, a USB audio device that can control a real 6581 and 8580 SID chip and natively playback most SID tunes.

SID hardware clones

* The SwinSID is hardware emulation of the SID using an Atmel AVR processor, also featuring a real SID player based on the Atmel AVR processor. * The V-SID 1.0 project (code name SID 6581D, 'D' for digital) from David was born in 2005. This project is a hardware emulation of the SID chip from the Bob Yannes's interview, datasheets. The V-SID 1.0 engine had been implemented in a FPGA EP1C12 Cyclone from ALTERA, on an ALTIUM development board, and emulates all the characteristics of the original SID, except the filter which is a digital version (IIR filter controlled by a CPU). * The PhoenixSID 65X81 project (2006) aimed to faithfully create the SID sound using modern hardware. The workings of a SID chip were recreated on an FPGA, based on interviews with the SID's creator, original datasheets, and comparisons with real SID chips. It was distinguished from similar attempts by its use of real analog circuitry instead of emulation for the legendary SID filter. However, the project was discontinued, because George Pantazopoulos, who was the head of this project, died on April 23, 2007, at the age of 29. * The

C64 Direct-to-TV The C64 Direct-to-TV, called C64DTV for short, is a single-chip implementation of the Commodore 64 computer, contained in a joystick (modeled after the mid-1980s Competition Pro joystick), with 30 built-in games. The design is similar to the A ...

emulates large portions the SID hardware, minus certain features such as (most notably) the filters. It reduces the entire C64 to a small circuit that fits into a joystick while sacrificing some compatibility. * The SIDcog is a software SID emulator running on the

Parallax Propeller The Parallax P8X32A Propeller is a multi-core processor parallel computer architecture microcontroller chip with eight 32-bit reduced instruction set computer (RISC) central processing unit (CPU) cores. Introduced in 2006, it is designed and sold ...

. All three channels can be emulated on one of the Propeller's eight COG's. * The ARMSID is a "plug & play" replacement of the MOS 6581 and MOS 8580 with analog inputs support. * The FPGASID is a FPGA based SID replica providing high reproduction quality of the original device including all features such as the audio filters and the paddle registers. The device is a full featured stereo solution and can replace two SID chips in a single SID socket. Hardware base is an Altera MAX10 FPGA.

Trivia

The Swedish electronic music duo Carbon Based Lifeforms released a track titled "MOS 6581" on their album '' Hydroponic Garden'' in 2003.

References

External links

SID in-depth information page
*
The 6581 SID Datasheet

SID programming info

{{DEFAULTSORT:Mos Technology Sid MOS Technology integrated circuits Sound chips Commodore 64 Commodore 64 music Video game music file formats Video game music technology

Design process

Manufacturing, remarking, and forgery

Features

Technical details

Revisions

Game audio

Emulation

Software emulation

Hardware reimplementations

Hardware implementations using the SID chip

SID hardware clones

Trivia

See also

References

Further reading

External links