Dio Pin Change Detect; Sample Rate (Interval); I/O Line Passing - Digi XBee Product Manual

DIO pin change detect

When "DIO Change Detect" is enabled (using the IC command), DIO lines 0-7 are monitored. When a
change is detected on a DIO line, the following will occur:
1. An RF packet is sent with the updated DIO pin levels. This packet will not contain any ADC samples.
2. Any queued samples are transmitted before the change detect data. This may result in receiving a
packet with less than IT (Samples before TX) samples.
Note Change detect will not affect Pin Sleep wake-up. The D8 pin (DTR/Sleep_RQ/DI8) is the only line
that will wake a module from Pin Sleep. If not all samples are collected, the module will still
enter Sleep Mode after a change detect packet is sent.
Applicable Commands: IC (DIO Change Detect), IT (Samples before TX)
Note Change detect is only supported when the Dx (DIOx Configuration) parameter equals 3, 4 or 5.

Sample Rate (Interval)

The Sample Rate (Interval) feature allows enabled ADC and DIO pins to be read periodically on
modules that are not configured to operate in Sleep Mode. When one of the Sleep Modes is enabled
and the IR (Sample Rate) parameter is set, the module will stay awake until IT (Samples before TX)
samples have been collected.
Once a particular pin is enabled, the appropriate sample rate must be chosen. The maximum sample
rate that can be achieved while using one A/D line is 1 sample/ms or 1 kHz. The modem will not be
able to keep up with transmission when IR and IT are equal to "1" and we do not recommend
configuring the modem to sample at rates greater than once every 20 ms.
Applicable commands: IR (Sample Rate), IT (Samples before TX), SM (Sleep Mode)

I/O line passing

You can set up virtual wires between XBee / XBee-PRO Modules. When an RF data packet is received
that contains I/O data, the receiving module can be setup to update any enabled outputs (PWM and
DIO) based on the data it receives.
I/O lines are mapped in pairs. For example: AD0 can only update PWM0 and DI5 can only update
DO5. The default setup is for outputs not to be updated, which results in the I/O data being sent out
the UART (refer to the IU (Enable I/O Output) command). To enable the outputs to be updated, the IA
(I/O Input Address) parameter must be setup with the address of the module that has the
appropriate inputs enabled. This effectively binds the outputs to a particular module's input. This
does not affect the ability of the module to receive I/O line data from other modules - only its ability
to update enabled outputs. The IA parameter can also be setup to accept I/O data for output
changes from any module by setting the IA parameter to 0xFFFF.
When outputs are changed from their non-active state, the module can be setup to return the output
level to it non-active state. The timers are set using the Tn (Dn Output Timer) and PT (PWM Output
Timeout) commands. The timers are reset every time a valid I/O packet (passed IA check) is received.
The IC (Change Detect) and IR (Sample Rate) parameters can be setup to keep the output set to their
active output if the system needs more time than the timers can handle.
Note DI8 cannot be used for I/O line passing.
XBee / XBee-PRO RF Modules 802.15.4 Product Manual
ADC and Digital I/O line support of the XBee/XBee-PRO RF module
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