As previous article , now the problem will be resolve .

Previously mentioned , I used the " 3-axis accelerometer(ADXL330) " connection to XBee1 use ADC mode , and XBee1 will sent data to XBee2 .

The XBee2 connection to Arduino , and the Arduino use USB transmission line connection to PC .

When I use ADC model , each data form I received liked 7E 0 E 83 56 78 1C 0 1 E 0 3 EC 3 EC 3 EE B4 .

And the data form is :

7E Start Delimiter 000E Length (14bytes from here to checksum) 83 API Identifier: 16-bit A/D 5678 Source address. 1C RSSI 00 Option Byte 01 Sample Quantity 0E00 Channel indicators 0E00=0000 1110 0000 0000 = A2, A1, A0 03EC Value for channel A0 03EC Value for channel A1 03EE Value for channel A2 B4 Checksum

Now how can I further analysis " 3 EC 3 EC 3 EE " ?

May need to back up a little. How is the ADXL330 output getting measured? According to the datasheet the ADXL330 is powered from 3V, with 3.3 I would expect being typical.

Per Table 1 on page 3 and Figures 13,14,15 of the datasheet http://www.sparkfun.com/datasheets/Components/ADXL330_0.pdf one would expect the output to be sitting at ~1.5V.

Where is the reading of 3EC coming from? 3EC hex = 1004 decimal. An arduino ADC running from 3.3V would output ~465 for a 1.5V input. An arduino ADC running from 5V would output ~307 for a 1.5V input. If the arduino ADC was using internal Vref of 1.1V and 1.5V was being sampled, a reading up towards 1023 might result (3FF).

What ADC and reference voltage is putting out 3EC?

Actually , there is no clearly marked on the accelerometer . So I guess it's ADXL330 .

They have 6 pins : VCC , ST , GND , X , Y , Z , respectively.

VCC connect to 3.3V , X connect to XBee's ADO(pin20) , Y connect to XBee's AD1(pin19) , Z connect to XBee's AD2(pin18) .

Finally I use Arduino development software , then click the " Serial Monitor " print result use "16hex" on the screen .

What ADC and reference voltage is putting out 3EC ? ? What's your mean ?

Ok, Per Xbee documentation, those three pins are Analog Inputs with a default state of Disabled: