New to SX chips

Javalin

Hello,

I am new to the SX chips, but have experience with the BS2 and Javalin Stamps.

I am looking to use the SX chip line to implement a i2c slave to control things like relays/darlintons via appropriate circuitry - and such like.

Does anybody have any experience with the SX and i2c slave stuff and could tell me:
1)· If this is possible?
2)· Level of difficultly?

Any other info for a SX newbie would be appriated!

Thanks for your help!

James

Jon Williams

Get Guenther Daubach's book: http://www.parallax.com/detail.asp?product_id=70002

It's a great book for learning the SX, and does cover I2C.· BTW, the MCP23016 is a great I2C device for IO ... and a lot easier than a roll-you-own solution.

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Jon Williams
Applications Engineer, Parallax
Dallas Office

James Newton

Better yet, get Guenther Daubach's implementation of an RS232 / i2c·unit "·to control things like relays/darlintons via appropriate circuitry - and such like" ready to go!
http://www.sxlist.com/techref/ubicom/rsi2o3i2c/index.htm



RS-232: This module is used to control external components via the I²C bus using simple command sequences sent and received via an RS-232 port from an application running on a PC, PDA, or other platform. The on-board MAX-232 level shifter insures there will be no signal level problems and allows for maximum cable length.

I²C Bus Master: The RS-232 / I²C-Adapter acts as an I²C master, and can perform the most frequently used read/write operations via the bus without the need for the application software to handle the I²C protocol. When the application sends one of the "macro command sequences", the adapter takes care of generating the start condition, transmitting the address plus the R/W bit, transmitting/receiving data bytes plus setting/reading the acknowledge bit, and finally generating the stop condition. All of this is transparent to the application software.

I²C low-level: To ensure compatibility, the adapter also allows the application software to directly "talk" to the I²C bus in order to allow communications with I²C devices that require non-standard sequences, using "low-level commands".

Relay Output: In addition, the RS-232 / I²C-Adapter comes with a reed relay which can be controlled by dedicated commands. This allows the application software to initialize various devices via the I²C bus before finally turning on the power supply for other components, for example. Besides this, the relay may also be used as a general-purpose isolated output.

General Purpose I/O: There are also four non-isolated outputs, and eight non-isolated inputs that can be set/read by specific adapter commands. The inputs also clock eight individual 16-bit counters that may be read/reset by designated adapter commands.

Monitor Mode: A special "Monitor Mode" is also available which turns the RS-232/I²C-Adapter into an I²C monitor, well suited to analyze an I²C bus system. In this mode, the adapter "listens" to the I²C bus, and sends information about all activities it recognizes on the bus via RS-232 to the application software without interfering with the bus communication itself.

Reliable WDT: As an additional option, a timer may be activated that resets the I²C-Adapter when new commands are not received within the specified time-out period.

Status Indicators: Thee LEDs are used to indicate the status of the RS-232/I²C-Adapter, the activities on the I²C bus, and the RS-232 lines.

The RS-232/I²C-Adapter is based upon a Ubicom/Parallax SX-28 microcontroller, clocked at 50 MHz. Single, pre-programmed chips are available for customers who want to integrate the RS-232/I²C-Adapter's functionality into their own hardware design (see below).

Specifications:

• Power Supply requirement: 5V DC, stabilized and filtered
• Relay Output: 1A, 250v DC (maximum ratings)
• Parallel Outputs: 4, TTL (0/5V), 30 mA sink/source
• Parallel Inputs: 8 TTL (0/5V), Schmitt-Trigger characteristics.
• RS-232 I/O: 115.2 kBaud, 8N1 (handshake is handled by the command protocol)
• I²C: 100kbit/s transfer rate (can be set to 20, 50, or 100 kbit/s)
• Dimensions: 2" x 2" (50mm * 50mm)
• Connectors: Two male 14-pin headers, 0.1" (2.54mm) spacing

Available Modules:

• $15 RS-232/I²C-Adapter Chip: Includes the pre-programmed SX chip
• $23 RS-232/I²C-Adapter Main Parts Kit: Includes PCB, SX controller, and a 50 MHz resonator.
• $40 RS-232/I²C-Adapter All Parts Kit: Includes PCB, and all components.
• $50 RS-232/I²C-Adapter A&T: Assembled and tested. <

All modules are shipped with a CD-ROM containing the documentation, schematics, assembly instructions, and the sample VB application project.

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James Newton, Host of SXList.com
james@sxlist.com 1-619-652-0593 fax:1-208-279-8767
SX FAQ / Code / Tutorials / Documentation:
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Javalin

thanks for your help guys!