Make your own free website on


First Program Example
Binary Clock Algorithm
Shift-and-Add Multiplication
Prime Numbers Benchmark
PWM LED Dimmer
Step Motor Controller
Sound Generator: Part 1
Sound Generator: Part 2
Random Number Generator
EPROM Data Storage
My Previous Z80 Project


My Z80 project: Z80/AM95 8-bit NANO COMPUTER

Z80/AM95 homemade 8-bit microcomputer



◦ Manufacturer: homemade by GG

◦ Model's name: Z80/AM95 8-bit NANO COMPUTER

◦ Typology: training microcomputer

◦ Number produced: 1

◦ Country of Origin: Italy

◦ Year: 2008-2010

◦ Style: vintage 1980's original components on perfboard

◦ Price: $0 -- (Not for sale)

◦ Ultimate aim: hobby and recreation, educational, chip-oriented retrocomputing, DIY electronics, 'Homebrewing' (designing and building of retro-styled computers)


◦ Processor: Z80 (MK3880P-10 8 bit CPU, ceramic purple, 2.5 MHz, -40 to +85C)

◦ CPU Datacode: 1980

◦ CPU Speed: 2.5MHz

◦ 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 :
7 Commands, 51 Statements (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 acknowledgment 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


DISCLAIMER & CREDIT: All data here reproduced are for educational and non-commercial purpose, following fair-use guidelines.

This is an INDIPENDENT AND UNOFFICIAL hobby site. Either Dr. Peter R. Rony or the Blacksburg group or Computer History Museum (Mountain View, CA) or other third-party DO NOT HAVE ANY ASSOTIATION with this work.

Author G.G. DOESN'T EARN ANYTHING FROM ADVERTISEMENT. This site is not in the business of making money. This site is visible thanks to the Free Web Hosting Tripod Service, so it is ad-supported: advertisement contents, costs and revenues are full managed by the service itself. Author does not have any involvement in them. The advertising links in the Site pages and in the pop-up windows are not Author's property. They can change and the Author is non-responsible about their contents and working. The Author is not responsible about the linked sites.
The information presented here is just that: INFORMATION. Use it at your own risk and for only non commercial purpose. The information here presented is believed to be technically correct and everything presented on this site is done so in good faith. Anyhow you (the reader) are responsible for anything that you might do as a result of reading this article. You assume complete and total responsibility for your actions! Author is not responsible for any misuse or damage coming from the reading and using this information.

Text and images from original typewritten Bugbooks I and II in 1974 are permission courtesy of Dr. Peter R. Rony, the original author and sole copyright owner of the Bugbooks I, II, IIA, III, V, and VI.

The background image on the header of each page of the site is "Sunset over western South America" photographed on 12 April 2011 by an Expedition 27 crew member on the International Space Station. (Image credit: NASA). On it I have merged titles and a my photo of TIL302 displays.

Texas Instruments data are Texas Instruments Copyright and reported by Courtesy of Texas Instruments.


TERM OF USE: With clear exception for texts and images which are not author's property, Gianluca G. freely authorizes you the downloading, printing and reproducing of APOLLO181 data, texts and images ONLY for non-commercial usage and ONLY if you give a clear reference to its source and project namewithout any right to resell or redistribute them or to compile or create derivative works.

Any rights not expressly granted herein are reserved.


Copyright (c) 2012 by Gianluca G. Italy