Gradiente Expert

Expert
Also known as	Expert XP-800
Manufacturer	Gradiente Eletrônica
Type	home computer
Release date	December 1985
Discontinued	1990
Operating system	MSX BASIC, MSX-DOS, CP/M
CPU	Zilog Z80A @ 3.58 MHz
Memory	64 KB–4096 KB (max.)
Removable storage	Cassette tape, cartridges, floppy discs
Graphics	TMS9918
Sound	AY-3-8910
Backward; compatibility	MSX
Successor	Expert GPC-1

The Expert (or Expert XP-800), made by Gradiente Eletrônica (to date best known as a game console and Hi-Fi equipment company) was the second and last MSX home computer launched in the Brazilian market, in the mid-1980s.^[1]

It was presented to the public at the 5th International Computing Fair, nicknamed "Informatica '85".^[2] The event took place at Anhembi Convention Center in the city of São Paulo from September 23 to 29, 1985.^[3] At the announcement, the computer was priced 65 ORTN s.^[4]

Its market release date was 1 December 1985, one week after Epcom's Hotbit, just in time for 1985's Christmas and with a massive media campaign on magazines, newspapers and TV. In the newspapers ads the initial offer price was Cr$ 4,640,000, or US$470 by the value at the time,^[5] or US$1,390 by Q2 2025.

The machine was a clone of the National CF-3000, with a computer case resembling a stereo system, a detached keyboard with a proprietary connector, no caps lock LED and no reset key,^[1] although the soft-reset could be achieved by pressing simultaneously the keys Shift + Control + Delete, while a hard-reset could be achieved by pushing in either of the cartridge slot covers, if they were free.^[6]^[7]

The Expert XP-800 was followed by the Expert GPC-1 ("Gradiente Personal Computer") in 1987, and by Expert Plus and Expert DD Plus (a system with a built-in 720 KB 31⁄2" floppy disk drive) in 1989.^[8]

The Expert users waited for an MSX2 machine, but Gradiente never produced it^[8] and discontinued the MSX line in 1990.

Versions XP-800/GPC-1

The two first versions had a graphite case and socketed chips, which caused a chronic problem: when the machine heated, the chips frequently pulled out and the system "froze". Also, the GPC-1, released in 1987, had a ROM slightly modified to solve an ASCII table compatibility issue with the other popular Brazilian MSX, Sharp's Hotbit.

Versions Plus/DD Plus

The last two versions had a black case and the problematic socketed chips were replaced by an ASIC. Nevertheless, the RAM was mapped to a secondary slot and, although it was straight by the MSX standards, caused a lot of crashes with programs who searched for memory in the wrong place. It did not contribute for the popularity of any of the Plus versions.^[8]

These machines used the MSX-Engine T7937A instead of the Z80A CPU of previous models.

Technical specifications

CPU	Zilog Z80A (XP-800 & GPC-1) @ 3.58 MHz MSX-Engine T7937A (Plus & DD Plus) @ 3.58 MHz
VDP	TMS9918
RAM	64 KB
VRAM	16 KB
ROM	32 KB
Keyboard	mechanic, 89 keys (with 4 cursor keys), number pad
Display	text: 40×24 rows; graphics: 256×192 pixels, 16 colours, 32 sprites
Sound	General Instrument AY-3-8910 (PSG), 3 voices, white noise
Ports	2 joystick connectors, TV out, RGB monitor out, sound out, tape recorder connector, parallel port, 2 cartridge slots
Storage	tape recorder (1200/2400 bit/s) or one or two external floppy drives (51⁄4", 360 KB or 31⁄2", 720 KB)

Peripherals

DR-1 ("data-corder"): tape recorder
JS-1: joystick
MBW-12: 12" green CRT monochrome monitor
TA-1: TV adapter
TM-1: 1200/75 bit/s modem with a RS-232C port

Notes

^ ^a ^b "Gradiente Expert XP-800". www.old-computers.com. Retrieved 2023-05-20.
^ "5ª Sucesu e 18º Cong. Nacional da Informática". Museu de Eventos - Anhembi (in Portuguese). 2015-05-18. Archived from the original on 2015-05-18. Retrieved 2023-05-20.
^ "Uma Vitrine Renovada" (PDF). VEJA (in Portuguese). No. 891. October 2, 1985. pp. 88, 89. Archived from the original (PDF) on May 18, 2015. Retrieved November 4, 2018.
^ "Informática 85: o que há de novo no setor" (PDF). Micro Sistemas (in Portuguese). September 1985. p. 36. Archived from the original (PDF) on 2015-05-18. Retrieved 2022-12-16.
^ "BRENO ROSSI shop advertising". O Estado de S. Paulo (in Portuguese). No. 33.987. December 15, 1985. p. 24.
^ "Gradiente Expert XP-800". MSX Resource Center. March 8, 2023.
^ "Expert". Museu da Computação e Informática - MCI (in Portuguese). 2004. Archived from the original on 2011-07-06. Retrieved 2023-05-20.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
^ ^a ^b ^c "GRADIENTE Expert Plus". OLD-COMPUTERS.COM.

[:0-1] "Gradiente Expert XP-800". www.old-computers.com. Retrieved 2023-05-20.

[2] "5ª Sucesu e 18º Cong. Nacional da Informática". Museu de Eventos - Anhembi (in Portuguese). 2015-05-18. Archived from the original on 2015-05-18. Retrieved 2023-05-20.

[Veja-3] "Uma Vitrine Renovada" (PDF). VEJA (in Portuguese). No. 891. October 2, 1985. pp. 88, 89. Archived from the original (PDF) on May 18, 2015. Retrieved November 4, 2018.

[MS48E-4] "Informática 85: o que há de novo no setor" (PDF). Micro Sistemas (in Portuguese). September 1985. p. 36. Archived from the original (PDF) on 2015-05-18. Retrieved 2022-12-16.

[Estadao-5] "BRENO ROSSI shop advertising". O Estado de S. Paulo (in Portuguese). No. 33.987. December 15, 1985. p. 24.

[6] "Gradiente Expert XP-800". MSX Resource Center. March 8, 2023.

[7] "Expert". Museu da Computação e Informática - MCI (in Portuguese). 2004. Archived from the original on 2011-07-06. Retrieved 2023-05-20.{{cite web}}: CS1 maint: bot: original URL status unknown (link)

[Gradiente-8] "GRADIENTE Expert Plus". OLD-COMPUTERS.COM.

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