LPWA Module Series
BG77 Hardware Design
BG77_Hardware_Design 31 / 76
Figure 6: Turn on the Module Using Keystroke
The power on timing is illustrated in the following figure.
VIL
≤
0.45V
VBA T
PWRKEY
500ms~1000ms
RESET_N
STATUS
(DO)
Inactive
Active
USB
NOTE
Inactive
Active
UART
Typ. 2.1s
Typ. 2.55s
Typ. 2.5s
Figure 7: Timing of Turning on Module
1. Make sure that VBAT is stable before pulling down PWRKEY pin and keep the interval no less than
30ms.
2. PWRKEY output voltage is 1.5V because of the voltage drop inside the Qualcomm chipset. Due to
platform limitations, the chipset has integrated the reset function into PWRKEY. Therefore, PWRKEY
should never be pulled down to GND permanently.
NOTES
