XBee®/XBee‐PRO® ZB SMT RF Modules
Bytes
Name
Description
Indicates which digital IO lines have sampling enabled. Each bit corresponds to one
digital IO line on the module.
• bit 0 = AD0/DIO0
• bit 1 = AD1/DIO1
• bit 2 = AD2/DIO2
• bit 3 = AD3/DIO3
• bit 4 = DIO4
• bit 5 = ASSOC/DIO5
• bit 6 = RTS/DIO6
• bit 7 = CTS/GPIO7
• bit 8 = Slp_Rq/DIO8
• bit 9 = On_Slp/DIO9
• bit 10 = RSSI/DIO10
• bit 11 = PWM/DIO11
• bit 12 = CD/DIO12
• bit 13 = DOUT/DIO13
• bit 14 = DIN/DIO14
2
Digital Channel Mask
For example, a digital channel mask of 0x002F means DIO0,1,2,3, and 5 are enabled
as digital I/O.
Indicates which lines have analog inputs enabled for sampling. Each bit in the analog
channel mask corresponds to one analog input channel.
•
•
•
•
•
bit 0 = AD0/DIO0
bit 1 = AD1/DIO1
bit 2 = AD2/DIO2
bit 3 = AD3/DIO3
bit 7 = Supply Voltage
1
Analog Channel Mask
A sample set consisting of 1 sample for each enabled ADC and/or DIO channel,
which has voltage inputs of 1143.75 and 342.1875mV.
If any digital I/O lines are enabled, the first two bytes of the data set indicate the state
of all enabled digital I/O. Only digital channels that are enabled in the Digital Channel
Mask bytes have any meaning in the sample set. If no digital I/O are enabled on the
device, these 2 bytes will be omitted.
Variable Sampled Data Set
Following the digital I/O data (if any), each enabled analog channel will return 2 bytes.
The data starts with AIN0 and continues sequentially for each enabled analog input
channel up to AIN3, and the supply voltage (if enabled) at the end.
The sampled data set will include 2 bytes of digital I/O data only if one or more I/O lines on the device are
configured as digital I/O. If no pins are configured as digital IO, these 2 bytes will be omitted. Pins are configured as
digital I/O by setting them to a value of 3, 4, or 5.
The digital I/O data is only relevant if the same bit is enabled in the digital I/O mask.
Analog samples are returned as 10-bit values. The analog reading is scaled such that 0x0000 represents 0 V, and
0x3FF = 1.2 V. (The analog inputs on the module cannot read more than 1.2 V.) Analog samples are returned in
order starting with AIN0 and finishing with AIN3, and the supply voltage. Only enabled analog input channels return
data as shown in the figure below.
To convert the A/D reading to mV, do the following:
AD(mV) = (A/D reading * 1200mV) / 1024
The reading in the sample frame represents voltage inputs of 1143.75 and 342.1875 mV for AD0 and AD1
respectively.
© 2010 Digi International, Inc.
93
DCD [ DIGITAL CORE DESIGN ]
