Sinclair Computer Hardware Factsheet ------------------------------------ Version 0.75 "Uncle" Clive Sinclair, inventor of the handheld pocket calculator, digital watch and small screen TV pioneer, founded Sinclair Research and developed the ZX80 microcomputer in March of 1979. Within a year, he had the ZX80 in the British market, selling for about 100 British pounds. In 1981, Sinclair Research developed and marketed the improved ZX81. Both computers were available in kit form, and had a dramatic effect on prices of computers that were available to home and hobbyist users. Other computer manufacturers were forced to lower prices drasticly, which put more computers in more homes in a shorter span of time. Indeed, the Sinclair line of computers, nearly forgotten by all except a dedicated remnant of hobbyists in this Pentium era,were a catalyst that accelerated the placement of computers as a common household and business item. This factsheet is intended to be a briefing of the hardware that comprised the Sinclair line of computers. It is intended to give a view at the chipset level as well as the hardware system level. It is a growing body of information as the details of this line of computers are compiled by its current devotees. Versions above 1.0 are intended to include third party hardware descriptions, since the third party developers of interfaces, mass storage, memory expansions, and peripherals have helped to keep the Sinclair computers a viable tool for personal and business use. Submission of facts that were omitted or are inaccurate in this version are graciously welcomed. My experience is with the T/S1000 and T/S2068, and many peripherals associated with these computers. My sources include some back issues of Sync, Update,T/S2068 Technical Manual and Syncware news. There is a large body of information about these machines residing in closets and stashed away in boxes that we need to liberate and make available to the curious and the perhaps eccentric souls of those who dare venture into the Sinclair Zone. Email submissions/corrections/rants directed to me may be directed to: Bob.Johnson@pdsig.com COMPUTERS --------- NOTE: The Sinclair line of computers used the Z80A 8-bit CPU and custom logic chips such as the ULA. The ZX81 and T/S1000 were of such simple low-cost design that they drove prices of competing computers way down, thus putting computers into the hands of millions of hobbyists and home users. Timex was licensed by Sinclair to sell Sinclair machines in designated countries around the world. Timex and Sinclair signed an agreement that precluded each other from competing in one another's territories, which is why you would rarely see a Timex/Sinclair in England and rarely see a Spectrum in Canada or the US. Eventually, independant dealers shipped both sets of machines to both sides of the Atlantic, and elsewhere. - ZX80 -- 4K Sinclair Integer BASIC ROM, 1K RAM, white plastic case, membrane keyboard, 32x22 UPPERCASE character monochrome display, RF modulated video output. Also available as a kit. - ZX81 -- 8K Sinclair Floating Point BASIC ROM, 1K RAM in a small black plastic case, membrane keyboard, 32x22 UPPERCASE character monochrome display, 64x44 graphics, RF modulated video output. Also available as a kit. - T/S1000 (Timex/Sinclair) -- American version of the ZX81. It is 100% compatible. In fact, early models had a ZX81 circuit board. Two 4x1K RAM chips replaced by single 8x2K RAM. It looks the same as a ZX81 except it has a Timex/Sinclair logo where the Sinclair logo of the ZX81 appears. - T/S1500 -- 16K RAM version of the T/S1000 with a new case design. Raised rubber chiclet keys. It is also 100% compatible with the ZX81. - ZX Spectrum -- 16K Sinclair BASIC ROM, 48K RAM, 16 color, 256x192 graphics,color attributes available in 8x8 pixel chunks, 512x192 graphics in two colors permitting 64x22 UPPER and lowercase characters. software BEEP tones for sound,raised rubber chiclet keys. - T/S2068 -- American version of the Spectrum. Has an additional 8K extension ROM, cartridge port, two joystick ports and AY-3-8912 sound chip with extra Sinclair BASIC commands to support these devices (STICK, SOUND). Packaged in a hard plastic silver case with nonstandard plastic keys. The TS2068 is Timex's re-engineered 48K Spectrum. It was released in Fall 1983 just before Timex Computer Corp folded in Spring 1984. A rogue arm of Timex in Portugal continued to sell TC2068s (same as TS2068) and TC2048s (an improved Spectrum - more on this in a sec) until 1989. They, of course,were only allowed to sell in non-Sinclair controlled marketplaces. Timex recognized that a 48K Spectrum would not continue being competitive in North America for long without changes being made. They developed two computers that were to be North America's debut of the Spectrum. One was called the TS2048 and the other the TS2068. The TS2048 was basically a 48K Spectrum w/ Kempston joystick and the advanced video modes of the TS2068 (see below). The TS2068 was a completely different computer with the Spectrum as its roots. Timex decided to only sell the TS2068. When sales over Christmas 1983 were disappointing, they pulled the plug. Timex of Portugal, no doubt encouraged by the Spectrum's popularity in Europe,continued to sell the TS2068 and offered the TS2048 as the TC2068 and TC2048 in parts of Europe, notably Portugal and Poland (got this info from two fellows from each of those countries who mentioned that the Timex computers were very popular there). When Timex pulled the plug, they dumped all their surplus TS2068s in Argentina. As for the number of TS2068s manufactured, I remember hearing a figure of 60,000 (but I'm not too sure). I have no idea about how many were sold by Timex of Portugal in Europe. Maybe someone from there will enlighten us? Here are the features of the TS2068: * Z80A processor clocked at 3.58Mhz * AY-3-8912 Sound Chip (same as 128K Spectrums) w/ clock 1.76475Mhz It is attached to different ports compared with the Spectrums, so you don't hear AY music when playing Speccy games (of course, it can be overcome). I mention the clock rate here because it is slightly different from the Spectrum's. * 72K (48K RAM; 24K ROM) which is bankswitched between three internal 64K memory banks called the HOME bank (16K ROM, 48K RAM), the EXROM bank (8K ROM; this one is not completely decoded and can only hold 8K), and the DOCK bank which is empty and is reserved for cartridges. The memory is bankswitched in 8K chunks. * The BASIC is a superset of 48K Spectrum BASIC (ie - has a few commands added). * A cartridge dock is located under a door on the right side of the computer. * Two joystick connectors (not compatible with any Sinclair joysticks) * RF out, Composite video available on jacks. RGB signals available on rear edge connector. * Hardware was nicely designed to support DMA and memory bankswitching. * Video Modes: - 256x192 pixel, 32x24 attributes (Spectrum screen) - 256x192 pixel, 32x192 attributes (extended colour mode) - Dual screen mode where you could flip between two Spectrum screens - 512x192 pixel monochrome As for Spectrum compatibilty: The tape I/O is the same so you can load Spectrum tape files. Spectrum BASIC is a subset of the TS2068's BASIC,so you can run Spectrum BASIC programs. The TS2068's ROM is different,though, so you can't run Spectrum m/c that makes use of the ROM. I have found that without the aid of a Spectrum emulator, I can run about 7% of the Spectrum's commercially available software. The Spectrum emulator is really a Spectrum ROM on cartridge (there are other forms) that is bankswitched into the lower 0-16K region. The top 48K region is filled with RAM. To the software this looks exactly the same as a 48K Spectrum. There are a few hardware reasons for incompatibilities (if you are really interested you can check out sna2jlo1.zip on nvg in /pub/sinclair/utils/ts2068 - you'll get a brief overview for reasons for incompatibilities). Using an emulator, I have tried about 400 games available on the net and have found 97% compatibility. - T/S2048 -- 16K RAM version of the 2068. - The ZX Spectrum +2 was the first product to be launched by Amstrad after its Sinclair takeover (boo!) Internally, it is the ZX Spectrum 128 (which was launched by Sinclair,while still owned by Sir Clive. The 128 has a ZX Spectrum + case, with '128K' label and exterior heat sink being the visible differences. There is a MIDI port too if my memory serves correctly). Externally, it looks typically Amstrad - tape deck, incompatible joystick ports, etc, in a grey box. - The ZX Spectrum +2A was launched after the +3. Internally, it is the ZX Spectrum +3 (the disk drive one). It even features the DOS, which upon bootup notifies which drives are available under the menu box. The ZX Spectrum +3DOS (and therefore the +2A) has some compatibility problems with earlier Speccy models, some old software won't work. Externally, it is exactly the same as the +2 but in black. The exterior label even reads +2 instead of +2A. The old 9V PSU as used on all Speccys was replaced in the +3 by a new one (presumably for the disk drive etc?),and the +2A takes a variant of that. - QL (rumored to mean "Quantam Leap") 68008 main CPU, 8049 coprocessor for keyboard and I/O, a decent first attempt at a "real" keyboard, 128K RAM, 48K ROM containing Sinclair Super BASIC and QDOS operating system. ROM and RAM are expandable. Connections include CPU expansion port, 2 RS-232 ports, TV and monitor, two joystick, and a cartridge port. The QL had a micro "wafer" drive built in and 6 additional drives could be connected. RAM --- - Timex/Sinclair 1016 16K RAM pack expanded the ZX81 and T/S1000 to 16K, and the T/S1500 to 32K RAM. It used 16Kx1 dynamic RAM chips. MASS STORAGE ------------ - Timex/Sinclair 2020 Program Recorder was a cassette recorder with a tape counter and a VU/LEVEL meter to optimise cassette LOADing and SAVEing. PRINTERS -------- - Timex/Sinclair 2040 Printer, AKA the Alphacom 32, was a 32 column line printer that used thermal paper for imaging. It was compatible with all Timex/Sinclair computer busses, including the Spectrum bus. Sinclair BASIC commands LPRINT and LLIST directed output to the printer, and COPY did a screen dump. MODEM ----- - The Timex/Sinclair 2050 modem, AKA the Westridge 2050 modem, was designed to be plugged into the expansion bus. It was manufactued by Anchor Automation,used the 8251 UART chip, and was capable of 300 baud. A simple modification that bypassed the analog modem portion of the unit permitted it to function as an RS-232 port that could accept a faster modem, as well as other serial devices. INTERFACE --------- - Interface 1 was designed to enable the Spectrum to have joystick and RS-232 capabilities. - Timex/Sinclair 1510 Command Cartridge Player was compatible with the ZX81,T/S1000 and T/S1500 bus. It allowed the use of ROM based software cartridges. - Timex/Sinclair 2090 Command Sticks were Atari/Commodore style digital joysticks that had an elongated base for holding in one hand while holding the stick in the other hand. The firing button was designed for thumb operation. VAPORWARE --------- NOTE: This section includes peripherals and options that may have been developed and prototyped, perhaps even some limited production, but never were available to the general public. By nature, some of this information may be rumor or apocyphal stories. It is still fascinating to wonder, what if? - BEU -- Bus Expansion Unit for the T/S2068. Was to plug into the expansion bus and offered bank switching RAM expansion, up to 16 MEGS, and buffering of bus signals so more peripherals could be plugged in. - 80 column printer -- Mannesman Talley printer with bus interface circuits - T/S2068 Disk Drive -- was submitted for FCC radio emission approval, used 3" disks, has two RS-232 ports, ROM/RAM and onboard CPU - T/S3068 Computer -- CPU and options unknown, but rumored to be competitive with the visionary Amiga line of computers. CONTRIBUTORS: ------------- Contributors to this factsheet include these fine Sinclair afficianados: Kurt.Prochnow@pebble.cts.com Paul Squires sealbrec@acs.ucalgary.ca (Alvin Albrecht) Much of this information was discussed on comp.sys.sinclair and email that was passed back and forth.