This is an old revision of the document!
Table of Contents
SBC-386EX rev 2.0 Board
Disclaimer: as of the end of 2018, the BIOS ROM is still a work in progress.
N.B.: The 2.0 board requires a 1-wire update (see section below).
Features
- 80386EX CPU running at 25Mhz or 33Mhz
- FPU socket for 387SX
- Serial I/O using CPU integrated 8250A
- DS1302 RTC and NVRAM
- 32Kb SRAM
- 72-pin DRAM supports 4Mb .. 64Mb
- IDE interface
- micro SD socket
- ROM socket for 64Kb .. 256Kb BIOS chip
- All of the on chip features of the -EX chip
Photos
Photo 1. Dan's board using the CPU mounted on a daughterboard.
Photo 2. John's board with the CPU board-mounted.
Photo 3. Two of the adapter boards for the 386EX.
Hardware Documents
| Filename | Size | Last modified |
|---|---|---|
| update-2018-02-18.txt | 432b | 2018-Feb-18 |
| sbc-386ex-2.0-sch.pdf | 499kb | 2018-Jan-21 |
| sbc-386ex-2.0-pcb.pdf | 850kb | 2018-Jan-21 |
| pld-386ex-2018-02-18.zip | 4kb | 2018-Feb-18 |
| sbc-386ex-2.0-kicad.zip | 1.4mb | 2018-Jan-23 |
| sbc-386ex-2-gerber.zip | 955kb | 2018-Jan-21 |
There is a Guide to the Schematic which may be of interest to some builders.
The current Kicad tools do not produce a very pretty Bill of Materials. This “CSV” (comma separated values) is edited to add additional information.
Board 2.0 to 2.1 (mandatory) update.
Adapter board
| Filename | Size | Last modified |
|---|---|---|
| adapter386ex-sch.pdf | 90Kb | 2017-Nov-08 |
| adapter386ex-kicad.tar.bz2 | 193Kb | 2017-Oct-09 |
| adapter386ex2mm-gerber.zip | 73Kb | 2017-Oct-09 |
Note: This adapter is not for other PQFP-132 chips. Power and Ground connections are specific to the 80386EX chip.
Software Tools
The software for the SBC-386EX has been developed under Windows using:
- The Netwide assembler, NASM 2.08
- Open Watcom 1.9 (2.0 should not be used)
In addition, certain tools, largely derived from the SBC-188 project will also be required: tools-2018-03-14.zip
Board Testing
Proper operation of the DRAM should be confirmed with: test1-2018-04-23.zip
The ROM images are distributed as *.HEX files in the archive. (Intel Hex)
