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{{Short description|Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica}}
{{Infobox computer
{{Infobox computer
|Photo = [[Image:TK90X.jpg|300px|TK90X — Brazilian ZX Spectrum clone]]
| Photo = [[Image:TK90X.jpg|300px|TK90X — Brazilian ZX Spectrum clone]]
|Type = [[Home computer]]
| Type = [[Home computer]]
|Released = {{Start date and age|1985}}
| Released = {{Start date and age|1985}}
|Discontinued =
| Discontinued =
|Processor = [[Zilog Z80]]B @ 3.5 MHz
| Processor = [[Zilog Z80]]A
|Memory = 16KB or 48KB RAM)
| Memory = 16KB or 48KB RAM
|OS = [[Sinclair BASIC]]
| OS = [[Sinclair BASIC]]
|unitssold =
| unitssold =
| compatibility = [[ZX Spectrum]]
| graphics = CMOS IC
| display = TV RF output (VHF channel 3), [[PAL-M]], [[PAL-N]], [[NTSC]], 256 x 192, 15 colours
| sound = Single channel 1-bit DAC
| manufacturer = Microdigital Eletrônica
| CPUspeed = 3.58 MHz
}}
}}
The '''TK90X''' was a Brazilian [[ZX Spectrum]] clone made in 1985 by [[Microdigital Eletronica|Microdigital Electrônica]], a company from [[São Paulo]], that had previously manufactured [[Sinclair ZX80|ZX80]] ([[TK80]], TK82) and [[Sinclair ZX81|ZX81]] clones ([[TK82C]], TK83 and [[TK85]]).<ref>{{Cite web |title=TK-90X Microdigital |url=https://www.old-computers.com/museum/computer.asp?st=1&c=945 |access-date=2023-01-19 |website=www.old-computers.com}}</ref><ref>{{Cite book |last=Penix-Tadsen |first=Phillip |url=https://books.google.com/books?id=DNOaDwAAQBAJ&dq=TK90X&pg=PT26 |title=Video Games and the Global South |date=2019-05-20 |publisher=Lulu Press, Inc |isbn=978-0-359-64141-3 |language=en}}</ref><ref>{{Cite book |url=https://books.google.com/books?id=86IwAAAAYAAJ&q=%22TK+90X%22 |title=Manchete |date=1985 |publisher=Block Editores |language=pt-BR}}</ref>


Reported TK90X sales in October 1986 were 2500 machines per month.<ref>{{Cite news |date=November 1986 |title=TK 95 chega ao mercado |pages=16 |work=Micro Sistemas |url=https://datassette.s3.us-west-004.backblazeb2.com/revistas/micro_sistemas_062.pdf}}</ref>

The '''TK90X''' was the first [[Brazil]]ian [[ZX Spectrum]] clone made in 1985 by [[Microdigital Eletronica]], a company located in [[São Paulo]], Brazil, that manufactured some [[Sinclair ZX81|ZX81]] clones before ([[TK82C]], TK83 and [[TK85]]) and a [[Sinclair ZX80|ZX80]] clones (TK80, TK82).<ref>http://www.old-computers.com/museum/computer.asp?c=945&st=1</ref>


==Technical details==
==Technical details==
[[File:TK90X DISPLAY.JPG|thumb|TK90X boot screen]]
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 — [[User-defined graphic|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 case was a little taller than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional [[Sinclair BASIC|Sinclar BASIC]] commands that did not exist in the Spectrums (<code>UDG</code> for user defined characters in the place of the [[Pound sign|£]] sign - including specific Portuguese and Spanish characters such as {{Key press|ç}} and {{Key press|ñ}}, as well as [[Diacritic|accented]] vowels - and the <code>Trace</code> function).<ref>{{Cite web |date=2019-03-27 |title=Comandos Exclusivos de la TK 90X |url=http://www.compuclasico.com/articulos.php?Enlace=tk90x/nota_tk90x |access-date=2023-02-21 |website=CompuClasico - Antigüedades Digitales|archive-url=https://web.archive.org/web/20190327180445/http://www.compuclasico.com/articulos.php?Enlace=tk90x/nota_tk90x |archive-date=2019-03-27 }}</ref>


There were two versions of the machine, with 16 and 48&nbsp;[[kilobyte|KB]] of RAM.<ref>{{Cite news |last=Woods |first=Tim |date=September 1987 |title=Brazil's TK 90X |volume=3 |pages=2 |work=Time Design |issue=6 |url=https://archive.org/details/TimeDesigns/Time%20Designs%20v3%20n6/page/n3/mode/2up}}</ref> They contained the same [[Zilog Z80|Z80A]] processor running at 3.58&nbsp;MHz,<ref>{{Cite web |title=TK-90X Microdigital Eletronica Ltda (Brazil) |url=https://www.1000bit.it/scheda.asp?id=1396 |access-date=2023-01-19 |website=1000 BiT}}</ref> [[Read-only memory|ROM]] chip and [[RAM]] chips (dynamic RAMs 4116 and 4416).
The two versions were the 16&nbsp;[[kilobyte|Kb]] and 48&nbsp;Kb of RAM. They contained the same processor ([[Zilog Z80|Z80A]]), running at 3.58&nbsp;MHz and a [[Read-only memory|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 Junction Transistor|Bipolar]] IC [[Uncommitted Logic Array|ULA]] from Sinclair/Ferranti. The modulator was tuned to [[VHF]] channel 3 and the TV system was hardware selectable to [[PAL-M]] (60&nbsp;Hz) as used in Brazil, [[PAL-N]] (50&nbsp;Hz) as used in Uruguay, Argentina and Paraguay and [[NTSC]] (60&nbsp;Hz) as used in USA and many other countries.


Microdigital reverse engineered a [[CMOS]] integrated circuit (IC) with similar functionality to the original [[Bipolar Junction Transistor|bipolar]] IC [[Uncommitted Logic Array|ULA]] from Sinclair/[[Ferranti]]. Most software written for the Spectrum ran on the TK90X, with some minor incompatibilities.
⚫
An improvement over the original ZX Spectrum was the sound output via modulated RF direct to the TV set instead of the beeper.


The TV modulator was tuned to [[VHF]] channel 3, with the TV standard being hardware selectable to [[PAL-M]] (60&nbsp;Hz) as used in Brazil, [[PAL-N]] (50&nbsp;Hz) as used in Uruguay,<ref>{{Cite book |last1=Abbate |first1=Janet |url=https://books.google.com/books?id=s515EAAAQBAJ&dq=TK90X&pg=PA211 |title=Abstractions and Embodiments: New Histories of Computing and Society |last2=Dick |first2=Stephanie |date=2022-08-30 |publisher=JHU Press |isbn=978-1-4214-4437-6 |pages=211 |language=en}}</ref> Argentina<ref>{{Cite book |url=https://books.google.com/books?id=6IIYAQAAIAAJ&q=%22TK+90X%22 |title=Visão |date=1986 |language=pt-BR}}</ref> and Paraguay and [[NTSC]] (60&nbsp;Hz) as used in USA and many other countries.
Most software written for the Spectrum ran on the TK90X, with some minor incompatibilities. Only three peripherals were released by Microdigital &mdash; a Joystick, a light pen interface and a parallel printer interface.


⚫
An improvement over the original ZX Spectrum was the sound output via modulated RF direct to the TV set instead of the internal [[Piezoelectric speaker|beeper]].
⚫
A Beta disc (48) interface was made by third party companies, called 'C.A.S. disk drive interface' (a near-clone from the original Beta disc interface), 'C.B.I. disk drive interface' (with a printer interface included) and 'IDS91' (with a printer interface included made by Synchron) or 'IDS2001ne' (these exclusively compatible only with the TK90X or TK95{no ZX Spectrum use possible},also from Synchron) (and also with a printer interface included).

=== Peripherals ===
Three [[Peripheral|peripherals]] were released by Microdigital: a [[joystick]], a [[light pen]] interface and a [[Parallel port|parallel printer]] interface.

⚫
A [[Beta Disk Interface|Beta Disc Interface]] was available by third party companies, called ''<nowiki/>'C.A.S. disk drive interface'<nowiki/>'' (a near-clone from the original Beta Disc interface), ''<nowiki/>'C.B.I. disk drive interface'<nowiki/>'' (with an included printer interface) and ''<nowiki/>'IDS91'<nowiki/>'' (with an included printer interface made by Synchron) or ''<nowiki/>'IDS2001ne''' (also with an included printer interface made by Synchron, but exclusively compatible with the TK90X and TK95).


==TK95==
==TK95==
{{Main|TK95}}
The TK90X was replaced by the [[TK95]], which had a different keyboard (professional) and case (identical to [[Commodore Plus4]]) and exactly the same circuit board and schematics. The motherboard was marked as TK90X. The unit had a few difference in the ROM that made the TK95 more compatible with the original ZX Spectrum. It used the same ULA chip, with only digital logic ports and the analog part outside the ULA chip, exactly as in the TK90X. It was reported that the TK95 provided more compatibility with the original ZX Spectrum (e.g., the game Mikie runs only on TK95, not on TK90X). E.g., the D1 diode was disconnected, some changes to the ROM were made. Curiously, some games became incompatible due to this modification. TK90X users in Brazil used to make a switch to choose the original TK90X (or TK95) ROM or the ZX Spectrum ROM internally, so they could use almost all Spectrum software.
The TK90X was replaced by the [[TK95]],<ref>{{Cite news |date=November 1986 |title=TK 95 chega ao mercado |pages=16 |work=Micro Sistemas |url=https://datassette.s3.us-west-004.backblazeb2.com/revistas/micro_sistemas_062.pdf}}</ref> which had a different keyboard and case (identical to the [[Commodore Plus4]]), while the circuit board and schematics remained unchanged (the motherboard was marked as TK90X). It also used the same ULA as the TK90X, with only digital logic ports and the analogue part outside the ULA chip.

This machine had a few ROM differences that made it more compatible with the original ZX Spectrum (e.g., the game [[Mikie]] runs only on the TK95, not on the TK90X). Some users created a switch the enabled choosing between the original TK90X, TK95 or ZX Spectrum ROM internally, in order to be able to run all of the Spectrum's software.


==Export model==
==Export model==
During that period Brazilians were not allowed to import computers, and therefore the TK90X became the first affordable color computer for Brazilians. It was successful in other Latin America countries, such as Uruguay, but the export model used a different circuit board and schematics, and an original Ferrati ULA form ZX Spectrum.
During the 1980s Brazilians were not allowed to import computers and therefore the TK90X became the first affordable color computer in the market.<ref>{{Cite web |last=Martins |first=Marcelo |date=2011 |title=Tudo Sobre: TK90X |url=http://www.tk90x.com.br/TK90X.html |access-date=2023-01-19 |website=Clube do TK90X}}</ref> It was successful in other Latin American countries, such as Uruguay and Argentina, as an export model using a different circuit board and schematics, and the same Ferranti ULA as the ZX Spectrum.


Because of its affordability, many commercial software programs were locally developed for the first time for use of small businesses in Latin America to run on the TK90X, and millions of users had their first computer experience with it.
Because of its affordability in Latin America, many commercial software programs were developed locally for small business use and millions of users had their first computer experience with the TK90.

There's an active user base of enthusiasts of this computer, with dedicated websites discussing software preservation, peripherals and [[Homebrew (video games)|homebrew]] development and modifications.<ref>{{Cite web |title=Clube do TK90X |url=http://www.tk90x.com.br/ |access-date=2023-01-19 |website=Clube do TK90X}}</ref><ref>{{Cite web |title=Implementação de uma saída A/V no TK90X/TK95 |url=http://www.luccas.com.br/index.php/8-bits/artigos/17-implementacao-da-saida-a-v-no-tk90x-tk95 |access-date=2023-01-19 |website=Luccas Eletrônica}}</ref>


== References ==
== References ==
Line 36: Line 54:


== External links ==
== External links ==
* [http://br.groups.yahoo.com/group/TK90X TK90X/95 Mailing list] - Mailing list about TK90X/95/Spectrum (English Speakers are Welcome)
* [https://archive.today/20130105142344/http://br.groups.yahoo.com/group/TK90X TK90X/95 Mailing list] - Mailing list about TK90X/95/Spectrum (English Speakers are Welcome)
* [http://sourceforge.net/projects/zesarux/ ZEsarUX - ZX Second-Emulator And Released for UniX] (GPL)
* [http://sourceforge.net/projects/zesarux/ ZEsarUX - ZX Second-Emulator And Released for UniX] (GPL)


Line 42: Line 60:


{{DEFAULTSORT:Tk90x}}
{{DEFAULTSORT:Tk90x}}
[[Category:Microdigital Eletrônica]]
[[Category:Computer-related introductions in 1985]]
[[Category:ZX Spectrum clones]]
[[Category:ZX Spectrum clones]]
[[Category:Goods manufactured in Brazil]]


{{computer-stub}}
{{Compu-hardware-stub}}

Latest revision as of 08:22, 16 February 2024

TK90X
TK90X — Brazilian ZX Spectrum clone
ManufacturerMicrodigital Eletrônica
TypeHome computer
Release date1985; 40 years ago (1985)
Operating systemSinclair BASIC
CPUZilog Z80A @ 3.58 MHz
Memory16KB or 48KB RAM
DisplayTV RF output (VHF channel 3), PAL-M, PAL-N, NTSC, 256 x 192, 15 colours
GraphicsCMOS IC
SoundSingle channel 1-bit DAC
Backward
compatibility		ZX Spectrum

The TK90X was a Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica, a company from São Paulo, that had previously manufactured ZX80 (TK80, TK82) and ZX81 clones (TK82C, TK83 and TK85).[1][2][3]

Reported TK90X sales in October 1986 were 2500 machines per month.[4]

Technical details

[edit]
TK90X boot screen

The case was a little taller than the original Spectrum and the keyboard placement was equal to the original keyboard, except for some additional Sinclar BASIC commands that did not exist in the Spectrums (UDG for user defined characters in the place of the £ sign - including specific Portuguese and Spanish characters such as ç and ñ, as well as accented vowels - and the Trace function).[5]

There were two versions of the machine, with 16 and 48 KB of RAM.[6] They contained the same Z80A processor running at 3.58 MHz,[7] ROM chip and RAM chips (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. Most software written for the Spectrum ran on the TK90X, with some minor incompatibilities.

The TV modulator was tuned to VHF channel 3, with the TV standard being hardware selectable to PAL-M (60 Hz) as used in Brazil, PAL-N (50 Hz) as used in Uruguay,[8] Argentina[9] 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 internal beeper.

Peripherals

[edit]

Three peripherals were released by Microdigital: a joystick, a light pen interface and a parallel printer interface.

A Beta Disc Interface was available by third party companies, called 'C.A.S. disk drive interface' (a near-clone from the original Beta Disc interface), 'C.B.I. disk drive interface' (with an included printer interface) and 'IDS91' (with an included printer interface made by Synchron) or 'IDS2001ne' (also with an included printer interface made by Synchron, but exclusively compatible with the TK90X and TK95).

TK95

[edit]
Main article: TK95

The TK90X was replaced by the TK95,[10] which had a different keyboard and case (identical to the Commodore Plus4), while the circuit board and schematics remained unchanged (the motherboard was marked as TK90X). It also used the same ULA as the TK90X, with only digital logic ports and the analogue part outside the ULA chip.

This machine had a few ROM differences that made it more compatible with the original ZX Spectrum (e.g., the game Mikie runs only on the TK95, not on the TK90X). Some users created a switch the enabled choosing between the original TK90X, TK95 or ZX Spectrum ROM internally, in order to be able to run all of the Spectrum's software.

Export model

[edit]

During the 1980s Brazilians were not allowed to import computers and therefore the TK90X became the first affordable color computer in the market.[11] It was successful in other Latin American countries, such as Uruguay and Argentina, as an export model using a different circuit board and schematics, and the same Ferranti ULA as the ZX Spectrum.

Because of its affordability in Latin America, many commercial software programs were developed locally for small business use and millions of users had their first computer experience with the TK90.

There's an active user base of enthusiasts of this computer, with dedicated websites discussing software preservation, peripherals and homebrew development and modifications.[12][13]

References

[edit]
  1. ^ "TK-90X Microdigital". www.old-computers.com. Retrieved 2023-01-19.
  2. ^ Penix-Tadsen, Phillip (2019-05-20). Video Games and the Global South. Lulu Press, Inc. ISBN 978-0-359-64141-3.
  3. ^ Manchete (in Brazilian Portuguese). Block Editores. 1985.
  4. ^ "TK 95 chega ao mercado" (PDF). Micro Sistemas. November 1986. p. 16.
  5. ^ "Comandos Exclusivos de la TK 90X". CompuClasico - Antigüedades Digitales. 2019-03-27. Archived from the original on 2019-03-27. Retrieved 2023-02-21.
  6. ^ Woods, Tim (September 1987). "Brazil's TK 90X". Time Design. Vol. 3, no. 6. p. 2.
  7. ^ "TK-90X Microdigital Eletronica Ltda (Brazil)". 1000 BiT. Retrieved 2023-01-19.
  8. ^ Abbate, Janet; Dick, Stephanie (2022-08-30). Abstractions and Embodiments: New Histories of Computing and Society. JHU Press. p. 211. ISBN 978-1-4214-4437-6.
  9. ^ Visão (in Brazilian Portuguese). 1986.
  10. ^ "TK 95 chega ao mercado" (PDF). Micro Sistemas. November 1986. p. 16.
  11. ^ Martins, Marcelo (2011). "Tudo Sobre: TK90X". Clube do TK90X. Retrieved 2023-01-19.
  12. ^ "Clube do TK90X". Clube do TK90X. Retrieved 2023-01-19.
  13. ^ "Implementação de uma saída A/V no TK90X/TK95". Luccas Eletrônica. Retrieved 2023-01-19.
[edit]


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