User`s guide

XBee Digital I/O Adapter
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Configuring inputs and outputs
As shown in the pinouts table, the XBee Digital I/O Adapter product has
four external terminals that can be set as either a digital input or a sinking
driver output.
The XBee module controls the sinking drivers on pins 11, 16, 12, 4 for
terminals 1, 2, 3, 4 respectively.
The AT commands to the XBee module for the output function are D4, D6,
D7, P2 for terminals 1, 2, 3, 4 respectively.
Outputs are activated (that is, the sinking function is turned on) by setting
high the corresponding XBee pin for the output that is desired. To set a
terminal high, set the corresponding AT command to value 5. To set a
terminal low, set the corresponding AT command to value 4. For example,
setting terminal 1 to high would call the AT command D4 and set it to value
5.
Since the input and output functions overlap, the input function is always
active and when the input function is desired, the output control pin for the
matching output must be set low (turns off the sinking function). This
feature can allow the inputs to monitor the output sinking operation if
desired.
Input/output specifications and characteristics
Exceeding the maximum or minimum safe input values will result in
damage to the unit.
Digital mode Specification Value
Digital Input Input type Non-inverting Schmidt trigger gate
Positive-going switching threshold ~1.6 VDC
Negative-going switching threshold ~1.0 VDC
Maximum safe input +30VDC
Minimum safe input -.5VDC
Input impedance ~1.5 Megaohms
Default level when no input applied Low
Digital Output Output type Open collector sinking driver
Maximum sink current 1.8ADC
Maximum off voltage +30VDC
Minimum safe input -.5VDC
Resistor pullups 10K ohms pulled up to 3VDC; switch-
selectable