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Xport: Physical Connection to a Microcontroller

 
The Xport module can be used with Lantronix' embedded integration kit (EIK), which costs extra, or it can be used on its own. It's designed for mounting on a printed circuit board (PCB). I've designed a few different PCBs for the Xport, listed below.

The Xport has one serial port and three configurable I/O pins. It operates on 3.3 volts, DC, and is not 5V-compliant. To use it with a PIC or BX24 or similar microprocessors that have TTL serial capability, you'll need some circuitry to convert from 5V to 3.3V. the circuit below comes from Lantronix, slightly modified by me, and works well. It's the schematic for my Xport carrier board. +5V input goes to pin 10 of Connector J1, and ground goes to pin 1 of J1.

The pin assignments can be found in the datasheet from Lantronix. There's more info, including links to the integration guide and other documents on the Xport home page.

If you're looking to fabricate a version of this board yourself, the gerber files are here. I made the original document in Eagle CAD, and orderd my boards from Advanced Circuits. You can also get boards made cheap by Sparkfun (tell them I sent you).

I got the components for my board from Newark and Digikey; here are the part numbers (note: my board does not have the 5V regulator or its decoupling capacitors):

Part Value Part No. Comments
C1 1.0uF Digikey 478-1836-ND Any polarized 1.0uF capacitor will do.
C2 10uF Digikey P828-ND Any polarized 10uF capacitor will do.
C3 0.1uF Digikey 399-2127-ND Any 0.1uF capacitor will do.
D1 1N5226B-T Newark38C7685
Digikey 1N5226BDICT-ND
These limit the input voltages on the input pins to 3.3V. DO-35 package
D2 1N5226B-T Newark38C7685
Digikey 1N5226BDICT-ND
These limit the input voltages on the input pins to 3.3V. DO-35 package
D3 1N5226B-T Newark38C7685
Digikey 1N5226BDICT-ND
These limit the input voltages on the input pins to 3.3V. DO-35 package
D4 1N5226B-T Newark38C7685
Digikey 1N5226BDICT-ND
These limit the input voltages on the input pins to 3.3V. DO-35 package
D5 1N5226B-T Newark38C7685
Digikey 1N5226BDICT-ND
These limit the input voltages on the input pins to 3.3V. DO-35 package
D6 1N5817 Newark 48F6702
Digikey,1N5817DICT-ND
This keeps the 3.3V regulator from overheating. DO-41 package
IC1 MIC2915033BU Newark 83F5900 I used the BU model, which is a surface-mount (TO-263) package. If you're building this circuit on a solderless breadboard, I recommend the BT model instead (TO220 package).
J1 Pin Headers Digikey A1920-ND These are just male straight or right-angle pin headers, 0.1-inch spacing. Get them from any electronics retailer.
LED1 LED3MM Digikey 160-1144-ND Any 3mm or 5mm LED will do.
R1 10K Newark 84N2322
Digikey 10KQBK-ND
these go with the zener diodes. 0207/10 package
R2 10K Newark 84N2322
Digikey 10KQBK-ND
these go with the zener diodes. 0207/10 package
R3 10K Newark 84N2322
Digikey 10KQBK-ND
these go with the zener diodes. 0207/10 package
R4 10K Newark 84N2322
Digikey 10KQBK-ND
these go with the zener diodes. 0207/10 package
R5 10K Newark 84N2322
Digikey 10KQBK-ND
these go with the zener diodes. 0207/10 package
R6 220 Newark 01H9259
Digikey 220QBK-ND
Current limiting resistor for LED1. 0207/10 package

(Note: this is a non-stock item at Newark, with a really long lead time. any other electronics retailer will sell the same resistor)

U2 X-PORT

You can use this same hardware setup with a MAX232 chip or hex inverter, to connect the Xport to a computer's RS-232 serial port as well. Just connect the lines marked "to microcontroller TX" and "to microcontroller RX" in the schematic above to the TX and RX pins of your MAX232 or hex inverter, and then connect the hex inverter to the serial connector ("to microcontroller TX" goes to pin 3 of a DB-9 connector, "to microcontroller RX" goes to pin 2). Then connect the ground of your serial connector (pin 5 of a DB-9) to ground, and you're all set. See the schematic below. Connecting this way is how you configure the Xport serially.

Once you've got the hardware connected, you're ready to move on to configuration.