NB-IoT Module Series
BC65 Hardware Design
BC65_Hardware_Design 21 / 55
The procedure of the modem entering PSM is as follows:
The modem requests to enter PSM in
“
ATTACH 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 a duration of T3412 (periodic TAU timer). Note that the module cannot request 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 either of the following cases:
⚫
After the T3412 timer expires, the module will exit from Deep Sleep mode automatically.
⚫
Pulling down PSM_EINT (falling edge) will wake up the module from Deep Sleep mode.
The timing of waking up the module from Deep Sleep mode is illustrated below.
VBAT
VDD_EXT
Running
Deep Sleep
Module
Status
PSM_EINT
≥ 100 ms
Figure 4: Timing of Waking Up Module from Deep Sleep
3.6. Power Supply
3.6.1. Power Supply Pins
BC65 provides two VBAT pins for connection with an external power supply. The table below describes
the module's VBAT and ground pins.
Table 9: Power Supply Pins
Pin Name
Pin No.
Description
Min. Typ.
Max. Unit
VBAT
42, 43
Power supply for the module
3.2
3.8
4.2
V
GND
1, 10, 27, 34, 36, 37, 40, 41
GND
-
-
-
-
