Gradiente Expert

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Gradiente Expert
Gradiente Expert GPC-1
Type home computer
Release date December, 1985
Discontinued 1991
Operating system MSX BASIC, MSX-DOS, CP/M
CPU Zilog Z80A/MSX Engine T7937A @ 3.58 MHz
Memory 64 KB–256 KB (max.)

The Expert, 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 mid-1980s. Released one month after Epcom's Hotbit (just in time for 1985's Christmas), the Expert model XP-800 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]

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 3½" disk drive) in 1988. The Expert users waited in vain for a MSX2 machine, but Gradiente never produced it[1] and discontinued the MSX line in 1991.[2]

Versions XP-800/GPC-1[edit]

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.[2]

Versions Plus/DD Plus[edit]

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.[1]

Technical specifications[edit]

CPU Zilog Z80A (XP-800 & GPC-1) @ 3.58 MHz
MSX Engine T7937A (Plus & DD Plus) @ 3.58 MHz
RAM 64 KB
VRAM 16 KB (Texas Instruments TMS9918)
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 disk drive (5¼", 360 KB or 3½", 720 KB)

Peripherals[edit]

Notes[edit]

  1. ^ a b c Gradiente Expert Plus at old-computers.com
  2. ^ a b (Portuguese)-The MSX in Brazil

External links[edit]