User Manual

ThingMagic Nano User Guide 8
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ENABLE Line
The ENABLE line (referred to as the SHUTDOWN line in the M6e) must be pulled HIGH or left
unconnected for the module to be operational. To shut down the module, the line is set LOW or pulled to
Ground. Switching from high to low to high is equivalent to performing a power cycle of the module. All
internal components of the module are powered down when ENABLE is set LOW.
The Enable line must be connected to a GPO line of the control processor. This will allow the processor to
reset the module into a default state should it become unable to communicate with the processor for any
reason. Pulling the Enable line low for 50 milliseconds will reset the module.
DC Power Requirements
The module is specified to operate with DC input levels of between 3.3V and 5.5V. All specifications are
maintained if the total input current is below 1 A. At 1 A, the internal Voltage regulator’s protection circuit
allows no more current to be taken in. This 1A current limit will be reached slightly sooner if current is drawn
out the Volt line or if the GPIO lines are supplying current to external circuits.
The most obvious impact of this 1A limit is that the module cannot be operated below 3.7 Volts when the
RF power output level is set to 27 dBm. This limit is fully explained in the next section.
The module will still operate if the DC input Voltage level falls below 3.3V, but its specifications are not
guaranteed. If the DC input Voltage falls below 3 VDC, a “brownout” self-protection function in the
processor will gracefully turn the module off so that the module will not be in an indeterminate state once
the voltage is restored.
RF Power Output Impact on DC Input Current and Power
The ThingMagic Nano supports separate read and write power levels which are command adjustable via
the MercuryAPI. Either power level can be set within the following limits:
• Minimum RF Power = 0 dBm
• Maximum RF Power = +27 dBm
NOTE: Maximum power may have to be reduced to meet regulatory limits, which specify the combined
effect of the module, antenna, cable and enclosure shielding of the integrated product.
Caution: The polarity of the ENABLE line is opposite from the 4-port M6e module.