HOMEMADE computer with Z80
by G.G. (Italy)
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DESCRIPTION:
◦ Manufacturer: homemade by GG
◦ Model's name: Z80/AM95 8-bit NANO COMPUTER
◦ Typology: training minicomputer
◦ Number produced: 1
◦ Country of Origin: Italy
◦ Year: 2008-2010
◦ Style: vintage 1980's original components on perfboard
◦ Price: $-- (Not for sale)
◦ Ultimate aim: hobby and recreation, educational, chip-oriented retrocomputing,
DIY electronics, 'Homebrewing' (designing and building of retro-styled computers)
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SPECIFICATIONS:
◦ Processor: Z80 (MK3880P-10 8 bit CPU, ceramic purple, 2.5 MHz, -40° to +85°C)
◦ CPU Datacode: 1980
◦ CPU Speed: 2.5MHz, 4 Hz, instruction stepping
◦ Co-processor: AM9511 ( C8231A 16 bit Arithmetic Processing Unit @ 2.5MHz)
◦ Co-processor capability: 16-Bit Integer, 32-Bit Integer, 32-bit Floating Point. In addition to the four basic operations, AM9511 can implement transcendental functions.
◦ Data bus width: 8 bit
◦ RAM: 16K SRAM (or 8K NVRAM + 8K SRAM)
◦ ROM: 8K Eprom (or 8K E2prom)
◦ Storage: NVRAM and/or external IBM PC disk equipment
◦ Display: six chars numeric red LED 7-segment display (TFK CQX87),
eight chars ASCII red LED 16-segment display (DL2416),
COKIN P003 filter to enhance LED's light
◦ Sound: on board 555 chip tone generator (seven notes of the major scale) with speaker
◦ OS: 8BASIC (C) an interpreted BASIC dialect resident in ROM : 3 Commands, 51 Stetements (of which 23 floating point mathematical functions) ; machine code (HEX)
◦ I/O Ports: bidirectional RS232 Serial Interface (USART 8251),
bidirectional PC IBM LPT parallel port (nibble mode 8255 PIO with software ACK),
memory mapped 8 bit parallel I/O
◦ Error detecting mode: RAM test (bit-to-bit memory and adjacent cells),
ROM test (checksum control),
Serial communication (parity bit, buffer size control and checksum control),
Parallel communication (software acknolegment and checksum control)
◦ 16 bit Checksum algorithm (c):
CheckSum = 65535 - Sum [(CheckSum [t0] + 8bit Data [t+1]) Mod 65280]
◦ Input: on-board hex keypad (74C923),
Dip-switches for binary programming
◦ Software on CD-ROM: Serial & Parallel interface communication with an IBM PC (running in Visual Basic for Windows XP using inpout32.dll and MSCOMM32.OCX)
◦ BIOS PROM programming: built-in hardware and software burner for EPROM and E2PROM, equipped with ZIF sockets
◦ Briefcase Computer Case for Z80 machine
◦ Circuit protections: fuse, voltage regulators, schottky diodes in reverse bias, 1.5KW transient voltage suppression (TVS) diodes
◦ Power Supply : 220 V - 20 VA
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