Operation
Sleep support
I/O line passing details
The same message is received for both I/O sampling and for I/O line passing. But I/O line passing only
occurs if IA matches the short or long address of the sending node or if IA is 0xFFFF to match a sample
from any node. The default value of IA is 0xFFFFFFFF, which prevents I/O line passing from occurring
on the node because no node has that address. Additionally, the receiving device must have a
matching value for output. For example, if an ADC0 sample is received, then P0 must be configured
with 2 for PWM output. Otherwise, the analog signal will not be reflected with a matching PWM signal.
Likewise, if the sample indicates that D2 is high, but D2 is not set to 4 or 5 on the receiving device,
then the D2 pin will not be affected by I/O line passing.
When a digital output pin is set to something different than its configured value, that pin may return
to its configured value after the time specified for the corresponding timer. T0 specifies how long D0
will hold its non-configured value and T1 specifies how long D1 will hold its non-configured value. A
value of 0xFF indicates that a pin holds the value of the input of the corresponding device indefinitely
and a value less than 0xFF specifies how many tenth second units the pin holds the non-configured
value.
For PWM outputs, PT timer applies to both PWM0 and PWM1. A value of 0xFF allows the PWM pin to
output a duty cycle reflective of the analog input indefinitely and a smaller value indicates how many
10th second units before PWM output reverts to the duty cycle specified by M0 or M1.
Output control
The IO (Digital Output Level) command controls the output levels of D0 through D7 that are
configured as output pins (either 4 or 5). These values override the configured output levels of the
pins until they are changed again (the pins do not automatically revert to their configured values after
a timeout.) You can use the IO command to trigger a sample on change detect.
Sleep support
Set SO (Sleep Options) bit 1 to suppress automatic wake-up sampling.
When a device wakes, it always performs a sample based on any active ADC or DIO lines. This allows
sampling based on the sleep cycle whether it be Cyclic Sleep (SM = 4 or 5) or Pin Sleep (SM = 1). Set
the IR (Sample Rate) parameter to gather more samples when awake.
For Cyclic Sleep modes: If the IR parameter is set, the device stays awake until the IT (Samples before
TX) parameter is met. The device stays awake for ST (Time before Sleep).
Sleep modes
Sleep modes enable the device to enter states of low-power consumption when not in use. In order to
enter Sleep mode, one of the following conditions must be met (in addition to the device having a
non-zero SM parameter value):
n
SLEEP_RQ/DTR (pin 9 on through-hole devices, pin 10 on surface-mount devices) is asserted
and the device is in a pin sleep mode (SM = 1, or 5)
n
The device is idle (no data transmission or reception) for the amount of time defined by the ST
(Time before Sleep) parameter.
Note ST is only active when SM = 4 or 5.
The following table shows the sleep mode configurations.
XBee/XBee-PRO S2C 802.15.4 RF Module User Guide
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ETC [ ETC ]
