TK90X
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| Type | Home computer |
|---|---|
| Release date | 1985 |
| Operating system | Sinclair BASIC |
| CPU | Zilog Z80B @ 3.5 MHz |
| Memory | 16KB or 48KB RAM) |
The TK90X was the first Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica, a company located in São Paulo, Brazil, that had manufactured some ZX81 clones (TK82C, TK83 and TK85) and ZX80 clones (TK80, TK82) before.
The case was a little higher than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional commands that did not exist in the Spectrums (for characters defined by the user — UDG — in the place of the 'Pound' symbol, and the 'Trace' function in BASIC), and included specific Portuguese and Spanish characters such as ç and ñ, as well as accented vowels.
The two versions were the 16 Kb and 48 Kb of RAM. They contained the same processor (Z80A), running at 3.58 MHz and a ROM chip, some RAM chips (old dynamic RAMs 4116 and 4416). Microdigital reverse engineered a CMOS integrated circuit (IC) with similar functionality to the original Bipolar IC ULA from Sinclair/Ferranti. The modulator was tuned to VHF channel 3 and the TV system was hardware selectable to PAL-M (60 Hz) as used in Brazil, PAL-N (50 Hz) as used in Uruguay, Argentina and Paraguay and NTSC (60 Hz) as used in USA and many other countries.
An improvement over the original ZX Spectrum was the sound output via modulated RF direct to the TV set instead of the beeper.
Most software written for the Spectrum ran on the TK90X, with some minor incompatibilities. Only three peripherals were released by Microdigital — a Joystick, a light pen interface and a parallel printer interface.
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