Gradiente Expert
 | |
| 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] although the soft-reset could be achieved by pushing in either of the cartridge slot covers.
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 1989. The Expert users waited in vain for an MSX2 machine, but Gradiente never produced it[1] and discontinued the MSX line in 1991.[2]
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.[2]
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.[1]
Technical specifications
| 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
- DR-1 ("data-corder"): tape recorder
- JS-1: joystick
- MM-12: 12" monochrome monitor
- TA-1: TV adapter
- TM-1: 1200/75 bit/s modem with a RS-232C port
Notes
- ↑ 1.0 1.1 1.2 Gradiente Expert Plus at old-computers.com
- ↑ 2.0 2.1 (Portuguese)-The MSX in Brazil
External links
- (Portuguese)-Gradiente Expert
- (Portuguese)-Gradiente Expert Plus/DD Plus