What is the SX-X10 The SX-X10 is an Embedded Ethernet device which allows you to control X10 Home Automation devices over the Internet.  SX-X10 uses Ubicom's Ethernet SX-Stack evaluation board, a custom serial interface cable, and custom software to control a wireless X10 "Firecracker" CM17A Control Module from any Web browser.  This SX-X10 was selected as the WINNER of SX-List's 2001 Fast Embedded Ethernet Design Challenge and Contest.  Many thanks go out SXList.com and Ubicom for making this contest possible, and for giving me the opportunity to learn more about the SX processor's "Embedded Internet" capabilities.

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Live Online Demo!

Sorry, the online demo is no longer available due to my ISP's inability to support static IP addresses.

Version 1.0 Features

• Embedded Web Server
  • The Ubicom example HTTP has been rewritten to deliver a full set of dynamic values.  These values can be substituted into your HTMl to enhance the GUI or debug the functions of the X10 interface.
• SX Virtual Peripheral interface for controlling the X10 CM17A "Firecracker"
  • Serial  Input/Output functions are interrupt driven giving plenty of CPU for the Ethernet processing.
  • Minimize interface hardware by using the Evaluation Board's onboard RS-232 level converters.
• HTML GUI
  • The GUI mimics the functions of X10's HR12A Remote Control.
  • Allows ON/OFF/DIM of X10 all modules of a single X10 House Code.
  • The GUI also records the "last known" state of the selected House Code's  X10 modules.
• X10 House Code Selection
  • The House Code can be selected by using the D0-4 jumper locations on the Evaluation Board's user port.
• Onboard X10 Command Push Button
  • The push button on the Evaluation Board has been programmed to turn on/off the X10 device assigned Unit Code 1.
• IP Routing
  • The Example Ethernet stack has been enhanced to provide static Default Routing.
  •  This allows the device to be connected to the Internet and/or placed behind a home firewall.

Hardware

CM17A and RS-232

The CM17A uses RS-232 DTR and RTS signals for communication. These +12V signals also provide power for the device. The phase relation of DTR and RTS changes on these lines determine if bits 1 or 0 are being sent to the CM17A.  Under normal usage, i.e. while plugged into the back of a PC, the DTR and RTS lines of the computer's RS-232 interface are manipulated by X10 software to send data to the CM17A, without interfering with most other uses of the PC's serial port.

SX-Stack and RS-232

The SX-Stack Evaluation Board has an onboard MAX232 line driver and level converter configured as a RS-232 DCE device.  Although this onboard RS-232 interface is not used by the SX-Stack HTML demo, it is needed by the utility programs to load HTML data into the onboard serial EEPROM.  Any hardware changes to this interface, must be reversible to allow debugging of the device, and programming of the serial EEPROM.

A Simple Interface The SX-Stack Evaluation Board's MAX232 line driver only provides two output drivers.  These drivers are connected to the DCE device's RXD and CTS for normal serial communication. However, the CM17A does not need the these signals, so we can steal the I/O ports and their drivers and use as DTR and RTS simply by creating a special pin-header to DB-9 connector.

 

Eval Board  Header Pin	DCE DB-9 Pin	DCE Function	DTE DB-9 Pin	DTE Function
3	2	RXD	7	RTS
9	5	GND	5	GND
6	8	CTS	4	DTR

This special connector allows the MAX232 to drive the RTS and DTR pins of the CM17A.  The original DCE connector can be used for debugging, and for programming the serial EEPROM.  It was also very handy to attach a RS-232 breakout box to the DB-9 connector while debugging the CM17A interrupt routines.

X10 House Code Selection

Although the interface will accept and transmit X10 commands for any of the 256 House/Unit combinations, the GUI can only display buttons for one House Code.  Initially I had hard coded the default X10 House Code selection.  While making some final changes to the code, I realized that the otherwise un-utilized User Port would be an easy means of setting the device's default House Code.

Although a rotary encoded hex switch can be attached to pins E0-E4 and VCC of the User Port, I've driven E0-E4's opposing pins D0-D4 high, which allows the House Code to be selected by directly jumping the pins on the User Port.  The unit must be reset by pressing the reset button, before the new House Code takes effect..

Push button X10 Unit control

The Evaluation Board also provides a single push switch for user control.  This push button as been programmed to switch on and off Unit "1" of the default House Code.  You can use that button to control an X10 device directly from the SX device.  This action is similar to the buttons on regular X10 wall modules.

Software

SX-X10 Version 1.0

• Source Code       (SRC)
• Assembler Listing (LST)

Assembler

• • SX-Link v 1.30 from Parallax

  Base Line code

  • Ubicom's Ethernet SX Stack Source Code.

  HTTP

  The SX-X10 implements a very basic HTTP server.  This server is based on the SX-Stack Demo program, but has been re-written to allow 128 dynamic code substitutions.   Every ASCII value in the HTML source above $7F is considered a special character, and forces the HTTP server to take a special action. The special character is replaced in the HTML output by a regular ASCII character <=$7F.

  HTML

  Here are the source HTML files which are loaded into the SX-X10 to provide the demo GUI. The odd symbols embedded in the HTML are SX-X10's special characters. These raw HTML files are processed by the SX-X10 replacing occurrences of special characters with the last known state of X10 devices.

  • REMOTE

    
    The GIF files which create the GUI were a particular challenge.  These pieces were scanned from an actual X10 HR12A Remote Control, then pieced together to form the interface. Because the Evaluation Board only has 32 KB of EEPROM memory, the GIF's all had to be dithered to only 16 colors to reduce their file size. The same 16 colors were used for all the GIF's in order to make them look like one big GIF when pieced together.  As much time as this process took, I should have created a cartoon illustration from scratch.

  • ABCC

    
    This oddly named page is the default page for the web server. Its name "/abcc.htm" hashes to the same internal lookup code as "/".

  • DEBUG
  • This is a hidden page used to test dynamic code substitution, and to debug the running device. The page lists all the special dynamic codes, as well as providing a memory dump of upper memory.  It was very useful for application debugging, after the HTTP server was functioning.
  • TEMPERATURE

    
    A short Demo of the SX boards Varistor/ADC based thermometer. Again, special characters replaced, this time with converted ADC values.

Reference Documentation

SX and Ubicom

SX-Tech

SX-List Fast Embedded Ethernet Design Challenge and Contest

Ubicom: Ethernet SX Stack Evaluation Kit

Ubicom, Inc. - Virtual Peripheral - Ethernet SX Stack Source Code

Ubicom Ethernet SX-Stack Demo

X10 Home Automation

X10