I2C from the S2B?

I would like to interface I2C sensors to a zigbee building automation system (with a Digi Gateway, using Bosch BMP085 pressure sensors). From what I understand, I can accomplish this pretty easily, just connect a programmable XBEE-PRO ZB (S2B model) to the I2C sensors, route power to both systems, and then program the Freescale processor on the XBEE-PRO/S2B to handle the I2C to ZigBee communication. Does this sound correct/doable?

From what I have read so far, the S2B model has a Freescale MC9S08QE32CFT. The MC9S08QE32CFT does I2C through the SDA/SCL on pins 35 and 36 (of the MC9S08QE32CFT). These pins seem to be mapped to pins 19 and 7 of the XBEE-PRO/S2B. I assume a I can just connect pins 19/7 to my I2C lines, apply the appropriate power, and then develop the software on the Freescale to collect data from the sensors and telemeter it over the ZigBee network.

Will this approach work? I would love to hear any suggestions or feedback.


The I2C from the MC9S08QE32CFT is connected, as well as the SPI.
You will probably need some pull up resistors, since I am not sure if the pull up strength of the MC9S08QE32CFT is sufficient for I2C recommendations. If you forgot to attach external pull up resistors you might get away with the internal pull-ups, but I wouldn’t recommend it.