Single board 8 bit computer with 512k of RAM and 512k of FLASH project

[FenTrac]

This is a project for a single board 8 bit computer with 512k of RAM and
512k of FLASH.
It offers more RAM than the typical 8 bit micrcontroller.

As a DIY project, it uses open source or free software.

The double sided circuit board was made using the
laser printer toner transfer method.

The boot software example included uploads intel hex file
programs to the board using a terminal program and
ascii file transfer protocol at 115200 baud.
It's interfaced to the host using a USB to TTL adapter cable.

The board uses 4 chips:
Z8S18033VSG 33 Mhz CPU
SST39SF040-70 4 megabit flash
AS6C4008 55ns 4 megabit RAM
74HCT42 decoder.

The Z8S180 has 2 - UARTS, Clocked Serial I/O, 2 - 16 bit timers,
a DMA controller, and Memory Mangement SFRs.

The board brings all the CPU's signals out to headers to
accommodate expansion cards.

The initial boot program was loaded into FLASH using an Arduino Mega
shield as the programmer. Sketch and schematics are included.

Attached is a zip file with source code and files used to build the
board, along with some construction tips.


One side of etched board


Completed board and mega programmer

 

[ahmed-agt]

Apart from assemblers can you recommend free c Compiler for this Zilog board.

 

[FenTrac]

The C compiler used to write the software included with this project is SDCC, SDCC is the small device C compiler. It is an open source C compiler available for Windows and Linux. It supports a number of processors including PIC, 8051 and Z180.
The C source files used for the project are included in the attached .zip file. Also included is a header file that includes definitions for the additional special function registers that the Z8S180 has compared to the Z180.
All the software I used in the project is free and available online.

 

[ahmed-agt]

Thanks. I want to make one single board 8 bit based computer for academic use to replace my old 8085 and 68 series from Motorola which I earlier made. Thank for your time.

 

[andre_luis]

I want to make one single board 8 bit based computer for academic use to replace my old 8085 and 68 series from Motorola which I earlier made

About only 12 years ago, when it were already quite available cores with 16 bits, I worked in a company whose flagship products were based in another 8-bit variant of the Z80 family, the Z84 which incorporates in a single chip various peripheral controllers (PIO, SIO, UART, etc ...), and on the board were also added other external than these. Although at first sight it might seem strange considering other core options, it was amazing how much this board was able to manage in terms of the quantity of features and OEM modules with whom board interfaced. I consider an excellent platform for teaching purposes, once it touches the concept of microprocessors rather than microcontrollers.

 

[FenTrac]

Thank you for your interest ahmed-agt,
The documentation included with the project is very brief, and aimed at construction of the board as a "do it yourself" project. The software included is very basic and just enough to start using the board. If a more complete manual is needed, let me know and I will try and put one together and post it here.

 

[ahmed-agt]

Thank you for response. As I wanted to build a contemporary board, However, I'm reading through the Zilog microprocessor family to pick from. Thanks.