101-1272 Rabbit Semiconductor, 101-1272 Datasheet - Page 71

• Manufacturer Part Number: 101-1272
• Description: KIT MESH NETWORK ADD-ON RCM4510W
• Manufacturer: Rabbit Semiconductor
• Type: Microprocessorr

Specifications of 101-1272

• Product: Modules
• Data Bus Width: 12 bit
• Processor Type: Rabbit 4000
• Sram: 512 KB
• Number Of I/os: 20
• Description/function: Computer Module
• Interface Type: Ethernet
• For Use With/related Products: RCM4510W
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 316-1158

6.3 Using the Sleep Mode
The RCM4510W RabbitCore module has two components that are involved when the
sleep mode is invoked — the XBee RF module and the Rabbit 4000 microprocessor.
End devices, unlike coordinators and routers, can enter a low-power sleep mode. This
sleep mode is controlled by the XBee RF module, and fully powers down the Rabbit 4000
microprocessor for significant savings in power use.
The sleep mode can only be initiated while the RCM4510W is in the Run Mode (see
Section 4.3.1 for more information on the Program Mode and the Run Mode).
Once the XBee RF module on the RCM4510W is operating in the sleep mode, it will peri-
odically wake up and poll its parent router or coordinator to determine whether there is an
incoming message. If one is found, the message will be received and the Rabbit 4000
microprocessor will be restarted. Otherwise the XBee RF module will return to sleep.
Depending on how the sleep mode is configured, the XBee RF module may also restart the
Rabbit 4000 microprocessor after a timeout has passed even if no message is received.
The sleep mode is controlled by the XBee RF module with a set of user-configurable
parameters. Although a parameter can be set with an AT command, the recommended pro-
cedure is to only initiate the sleep mode using either the
the
The most important parameters are ST, SP, and SN. Together they control the duration of
sleep and wake times.
• ST is measured in milliseconds, and controls the amount of time the XBee RF module,
• SP is measured in 0.01 second intervals and controls the length of sleep for the XBee
• SN determines how many multiples of SP the radio will sleep before waking up if no
User’s Manual
and consequently the Rabbit microprocessor, will stay awake waiting for RF or serial
data before going to sleep. If any data are received, the ST counter will be reset. The
Rabbit 4000 microprocessor needs approximately two seconds to boot and reinitialize
the XBee RF module, so the value of ST must be at least 2000.
RF module. The XBee RF module will operate in a low-power mode for the time spec-
ified in SP, and then wake up briefly to poll its parent for a message. Depending on the
value of SN, the XBee RF module may then either return to sleep or wake up the Rabbit
4000 microprocessor. There are several important considerations for SP.
message was otherwise received.
xb_sleep()
- The ZigBee parent (coordinator or router) can buffer a message for only 30 seconds,so SP must be
- While SP is measured in 0.01 second intervals, it only has a 0.25 second resolution, and any value
- The overhead of polling for a message was tested internally and was found to be approximately 20
set to no more than 28 seconds.
sent to the XBee RF module is rounded automatically.
ms. Thus a hypothetical sleep with SN = 100 and SP = 100 will not wake the Rabbit microproces-
sor until 102 seconds have elapsed (rather than the expected 100 seconds). The polling time may be
sensitive to network conditions and firmware version, so you should perform your own testing if
timing is critical.
function call.
zb_Rabbit_poweroff()
or
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