Product Info

NB-IoT Module Series
BC660K-GL Hardware Design
BC660K-GL_Hardware_Design
3-22
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When the modem remains in PSM and the AP is in idle mode, the module will enter deep sleep mode.
The procedure of the modem entering PSM is as follows:
The modem requests to enable PSM in ATTACH REQUEST or TAU REQUEST message during
ATTACH/TAU (Tracking Area Update) procedure. Then the network accepts the request and provides an
active time value (T3324) to the modem and the mobile reachable timer starts. When the T3324 timer
expires, the modem enters PSM for the duration of T3412 (periodic TAU timer). Please note that the
module cannot request entering PSM when it is establishing an emergency attachment or initializing the
PDN (Public Data Network) connection
When the module is in deep sleep mode, it will be woken up in the following cases:

After the T3412 timer expires, the module will exit deep sleep automatically.

Send an AT command to the module (this AT command will be lost), pull down the MAIN_RXD, and
in falling edge, the module will be woken up from deep sleep.

Pulling down PSM_EINT (falling edge) will wake up the module from deep sleep.
The timing of waking up the module from PSM is illustrated below.
Figure 4: Timing of Waking up Module from PSM
3.5. Power Supply
3.5.1. Power Supply Pins
The module provides two VBAT pins for connection with an external power supply. The table below
describes the module's VBAT and ground pins.