AMD Geode: Difference between revisions

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Note that the IDE connector on the board is 2.0mm pitch, not the standard 2.54mm pitch most IDE cables use.
Note that the IDE connector on the board is 2.0mm pitch, not the standard 2.54mm pitch most IDE cables use.
TODO: Look at board again and validate and clarify these specifications.


TODO: Add photos
TODO: Add photos

Revision as of 13:00, 30 March 2022

I have a board with an AMD Geode CPU for some light retrocomputing development. This page details it and whatever I get up to with it.

See AMD Geode/Troubleshooting for details on the troubleshooting process.

See AMD Geode/Video 1 for details on the video production about the troubleshooting process.

See AMD Geode/Video 2 for details on the second video production.

Motivation

For a while I've been searching for a small computer with these requirements:

  • Runs real mode DOS programs
  • Has a somewhat antiquated CPU
  • Has an Ethernet card and DOS packet driver
  • Doesn't consume too much power

The use case here is to run my Twitch DOS Bot I've been developing over the years.

After the searching I found that there were a few systems that could approximate this:

  1. A Raspberry Pi running DOSBox-X
  2. Thin client machines that used VIA CPUs
  3. Expensive single-board computers using a Vortex86 chip
  4. Cheaper 86Duino boards
  5. An old Eee PC 1000HA I had

I eventually decided to go with option 1, a Raspberry Pi emulating DOS.

At least, until I saw an offer on eBay: a used Advantech PCM-9375F for only $50 AUD, which is over $400 less than new.

Why such a huge discount? Video output is broken. Which means you can't really do much with this machine. This at minimum would let me run by Internet-connected DOS bot and talk to DOS over a serial port.

I've also not had an x86 board with GPIO before, so that seems like something fun to play with.

I bought it on November 7 2021 and received it on November 12 2021.

Board specifications

The PCM-9375 A3 specifications shows these points that interest me:

  • AMD Geode LX800 500 MHz CPU (see the AMD Geode LX Processors Data Book for more information)
  • AMD Geode CS5536 chipset (see the AMD Geode CS5536 Companion Device Data Book for more information)
  • Dual RTL8139 10/100 Mbps Fast Ethernet (second requires breakout board that I have)
  • 5V power supply (12V needed for optional LCD)
  • CompactFlash storage
  • 3 RS-232 serial interfaces (only the main serial interface is given a port)
  • 8 GPIO pins (you don't see x86 boards with GPIO often)
  • No nopl instruction support (not documented)

Note that the IDE connector on the board is 2.0mm pitch, not the standard 2.54mm pitch most IDE cables use.

TODO: Add photos

Setup

For power I use a USB to Molex fan adapter. These come with the 5V USB connected to the 12V pins on the Molex connector in order to run a 12V fan at a lower voltage. With a little effort you can pry them out and put them in the 5V pins on the connector.

For storage I'm using a CompactFlash card. Nothing fancy.

For serial I'm using a DB9 null modem cable with partial handshaking. I tried buying one from eBay first but instead got a straight through cable instead. See my serial ports page for more information.