| Name | Sinclair ZX Spectrum 48K |
| Codename | ZX82 (being the popular ZX81's successor) |
| Made by | Sinclair Research Ltd., Cambridge |
| Released | - 1984 (this ISSUE 6A machine)
- the first ZX Spectrum appeared in April 1982
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| Serial-No. | 005-511618 |
| Additional info | sinclair
ZX SPECTRUM PERSONAL COMPUTER
PATENT PENDING
MADE IN UK |
| Board-info | |
| CPU | Zilog Z80A- the Z80 was an 8 bit CPU with a 16 bit address bus, which enabled it to access an address space of 64 KBytes directly. It could also be considered a heir to the popular Intel 8080 - in addition to its own instruction set, it also contains all i8080 instructions for compatibility
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| Speed | 3.54690 MHz |
| RAM | PCF1306P ULA (address decoding/ multiplexing)- 48 KBytes:
- RAM bank 2 is, in most Spectrums, fitted with 64Kx1 DRAMs, although they can only be addressed as 32Kx1 anyway. Reason is that Sinclair bought RAMs of a certain defective charge
(the second half of their capacity unaccessible), to reduce the cost
- the Spectrum 16K was the same but came with only bank 1 fitted
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| ROM/ Native OS | Sinclair ZX Spectrum BASIC 16K
- contains the operating system and BASIC interpreter
- extended capabilities compared to its ancestors' 8K BASIC, such as an ASCII character set or support for the machine's advanced features
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| Keyboard/ Layout | Rubber keyboard- 40 keys/ US (QWERTY)
- 183 functions, plus 8 for color selection, auto-repeat
- The later Spectrum+ (1984) had a standard-keyboard similar to that of the Sinclair QL
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| Graphics | Ferranti 6C001E-7 main ULA (TV-output)- Max.Res.: 256x192 pixels
- Text: 32x24 characters with graphical charset
- Max. Colors: 8 (but only 2 usable per 8x8 pixel-square)
- this machine's a PAL-version
- in both Sinclair ZX80 & ZX81, the CPU alone generated the TV-output. Using a dedicated IC here was a great leap forward
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| Sound | created by ULA- integrated 40 ohm loudspeaker
- 10 octaves (130 semitones) via BEEP-command (BASIC)
- can be connected to an external amplifier (via jack-sockets)
- 3rd party expansions (i.e. with GI AY-3-8910 or 8912) were also available
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| Media | - standard Audio-cassettes (via standard cassette-recorder, 1500 baud)
- later: Sinclair ZX Microdrive, which stored up to 85 KBytes on a small tape cartridge, transfer speed was about 15 KBytes/s. The microdrive could only be used in connection with the Interface 1, and although being a cheap and fast solution these days, its cartridges were known to be little reliable
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| Input/ Output | the 6C001E-7 ULA is also used here (e.g. port I/O)- 54 pin male edge conn. expansion slot
- RF TV-out
- 3.5mm jack socket headphones-out ('EAR')
- 3.5mm jack socket microphone-in ('MIC')
- 9V DC-in
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| Miscellaneous | - The ZX Spectrum was the direct successor to the ZX81 (thus also called ZX82) and Sinclair's first bigger success in the computer markets
- Like its above-mentioned ancestor, it was a low-cost machine. It also used standard audio-cassettes as media and had a cheap rubber keyboard. And just like the ZX81's, the machine's keyboard also provided up to 5 functions per key - some keys even have six!
- There were two versions:
- the Spectrum 16K had (as the name implies) only 16 KBytes, but could be expanded to 48 KBytes easily (via empty RAM sockets)
- the Spectrum 48K was the same, except for it came pre-equipped with 48 KBytes RAM
- In 1984, Sinclair introduced the Spectrum+ with a QL-like keyboard, because a major complaint about the earlier Spectrum was its bad keyboard. However, a Spectrum+ upgrade kit was available for the old machines (which was more or less a Spectrum+ case and keyboard)
- Later followed the Spectrum 128K (1985) and, after AMSTRAD had bought the rights on Sinclair-computers, Spectrum +2 and Spectrum +3. All three had a better BASIC and a new three-channel soundchip, similar to that of the ATARI ST. Spectrum +2 and +3 also had an internal cassette-recorder, similar to AMSTRAD's CPC464
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