Datasheet

RN171
DS70005171A-page 10  2014 Microchip Technology Inc.
2.8 Power Management
The module supports an ultra-low power sleep state,
from which it can wake for a range of detected reasons.
It transitions from asleep to CPU-active in 1.7 ms, and
CPU active to network connection in less than 35 ms
(typical). The RN171 also supports a keep-alive doze
state that provides an instant transition to a wake state.
2.8.1 FORCE AWAKE
The RN171 may be forced awake by asserting the
FORCE_AWAKE pin for at least 245 ms. If the
FORCE_AWAKE pin remains asserted, the module is
prevented from sleeping or dozing.
2.8.2 POWER SUPPLY
For supply voltages in the range of 3.0 to 3.7 volts, con-
nect the module using the power supply (no boost cir-
cuit). Refer to Figure 3-1 for an example.
2.8.3 BATTERY BOOST CONTROL
CIRCUIT
The RN171 includes a battery boost control circuitry for
battery voltages in the range of 1.8 to 3.3V. Five exter-
nal components as shown in Figure 3-2 make up the
battery boost circuit.
2.9 Module Reset
There are several ways to Reset the module:
• A Power-On Reset is generated automatically
when power is applied. This Reset is intended to
initialize the module when a new battery is con-
nected.
• Perform an external Power-On Reset by pulling
the RESET pin low.
• Perform a soft Power-On Reset using software
commands.
• A Reset can be triggered by a critical event, such
as a brownout, generated if the supply voltage
drops below the minimum operating voltage
2.9.1 BROWN-OUT DETECTION
The RN171 includes a brown-out detector that holds
the module in Reset if the battery voltage falls below
the minimum operating voltage.
WARNING
The battery boost circuit should not be operated with
battery supply voltages above 3.3 volts.
Note: If the RN171 module is used in battery
applications, it is highly recommended
that a voltage supervisory device be
employed.