SparkFun Forums

[KamPutty]

Hi all,

Okay, I know this is something stupid on my end!

I want to wire a xbee module. This is my setup

#1. XBEE mounted on XBEE Explorer Regulated (http://www.sparkfun.com/products/9132)
#2. RS232 shifter (http://www.sparkfun.com/products/8780)

DOUT --> TX
DIN --> RX

Shared GND. They both tap into the same ground

3.3v --> VCC on explorer board
3.3v --> VCC shifter

When I receive data via wireless, I do see the "RX" Blue LED light up on xbee side, and see the "TX" led light up on the shifter side

When I put a analyzer on the shifter, I get junk!
When I connect a DB9 to the shifter and attach to computer, nada.

Thoughts?

[KamPutty]

Also, just to get clarification...

On the shifter, looking at the top of the board, the db9 looks like this

x x x x x
x x x x

Which pin is the ground?

If I scope it out, it looks like the top left is ground or pin #5
So, the pins are

5 4 3 2 1
6 7 8 9

5=ground
3=RX
2=TX

Yes?

[waltr]

Look again at the Shifter schematic.
RX drive the BASE of one transistor so this means data goes into this pin and would be connected to the DOUT pin of the XBee.
Then TX is on the other transistors COLLECTOR and is an output from the transistor so it drive the DIN line of the XBee.
This is the logic level side.

On the RS232 side is another complication. There are two types of 9 pin serial cables. One is straight through, Pin 2 to pin 2, pin 3 to pin 3. The other is a cross-over the connects pin 2 to pin 3 and pin 3 to pin 2.
You'll have to do some research and measuring to determine which cable you have and which you need.

Signal naming for serial communication lines is confusing since TX on one device is the RX on the other device. But not all data sheet etc label to serial lines in this manner. Just look at the Shift schematic.
From the DB9: RS_OUT connects through to RX and RS-IN connects through to TX. But the data flow in RX to RS_OUT and RS-IN to TX.

The LEDs on the Shifter mean:
TX LED is the data to the XBee
RX LED is data from the XBee.

Hope this helps.

[waltr]

Also, just to get clarification...

On the shifter, looking at the top of the board, the db9 looks like this

x x x x x
x x x x

Which pin is the ground?

If I scope it out, it looks like the top left is ground or pin #5
So, the pins are

5 4 3 2 1
6 7 8 9

5=ground
3=RX
2=TX

Yes?

Pin 1 on the DB9 is the pin with a square pad.

Look at the Shifter board picture.
It is easy to see that the DB9 only has three pins connected with board traces. Traces from pins 2 & 3 go to the transistor array chip and pin 5 goes to cap C4.

[KamPutty]

thanks all!

My issue was that I had DOUT wired to TX, and DIN to RX! (How did I do that?!)

Swapped the pins, and viola!

Thanks again gang.

~Kam