User's Guide

Review Copy 11-6-10
ThingMagic Micro Family User Guide
30
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Power Modes
The Power Mode setting (set in /reader/powerMode) allows the user to trade off increased RF operation
startup time for additional power savings. The details of the amount of power consumed in each mode is
shown in the table under Micro Power Consumption. The behavior of each mode and impact on RF
command latency is as follows:
• PowerMode.FULL – In this mode, the unit operates at full power to attain the best performance
possible. This mode is only intended for use in cases where power consumption is not an issue. This is
the default Power Mode at startup.
• PowerMode.MINSAVE – This mode may add up to 50 ms of delay from idle to RF on when initiating an
RF operation. It performs more aggressive power savings, such as automatically shutting down the
analog section between commands, and then restarting it whenever a tag command is issued.
• PowerMode.SLEEP – This mode essentially shuts down the digital and analog boards, except to power
the bare minimum logic required to wake the processor. This mode may add up to 100 ms of delay from
idle to RF on when initiating an RF operation. PowerMode.SLEEP is not supported when using the
USB interface. Using the setting PowerMode.MEDSAVE is the same as SLEEP.
NOTE: See additional latency specifications under Event Response Times.
Event Response Times
The following table provides some metrics on how long common Micro operations take. An event response
time is defined as the maximum time from the end of a command (end of the last bit in the serial stream) or
event (e.g. power up) to the response event the command or event causes.
Event Response Times
Start Command/
Event
End Event
Time
(msecs)
Notes
Power Up
Application Active (with
CRC check)
1500
This longer power up period should
only occur for the first boot with new
firmware.
Power Up
Application Active
120
Once the firmware CRC has been
verified subsequent power ups do
not require the CRC check be
performed, saving time.
Tag Read
RF On
20
When in Power Mode = FULL
Tag Read
RF On
50
When in Power Mode = MINSAVE
Tag Read
RF On
120
When in Power Mode = SLEEP
Change to MINSAVE
PowerMode.MINSAVE
5
From Power Mode = FULL
Change to SLEEP
PowerMode.SLEEP
5
From Power Mode = FULL
Save and Restore Configuration
The Micro supports saving module and protocol configuration parameters to the module flash to provide
configuration persistence across boots. This was introduced to support Autonomous Operation, but can
also be used to reduce the amount of communication necessary to bring a module up to operating state
following a reboot. The parameters that can be saved include: