LTE Module Series
EC21 Hardware Design
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The reset scenario is illustrated in the following figure.
V
IL
≤0.5V
V
IH
≥1.3V
VBAT
≥150ms
Resetting
Module
Status
Running
RESET_N
Restart
≤460ms
Figure 16: Timing of Resetting Module
1. Use RESET_N only when turning off the module by
AT+QPOWD
command and PWRKEY pin failed.
2. Ensure that there is no large capacitance on PWRKEY and RESET_N pins.
3.9. USIM Card Interface
The USIM card interface circuitry meets ETSI and IMT-2000 SIM interface requirements. Both 1.8V and
3.0V USIM cards are supported.
Table 9: Pin Definition of the USIM Card Interface
Pin Name
Pin No. I/O
Description
Comment
USIM_VDD
14
PO
Power supply for USIM card
Either 1.8V or 3.0V is supported
by the module automatically.
USIM_DATA
15
IO
Data signal of USIM card
USIM_CLK
16
DO
Clock signal of USIM card
USIM_RST
17
DO
Reset signal of USIM card
USIM_
PRESENCE
13
DI
USIM card insertion detection
USIM_GND
10
Specified ground for USIM card
NOTES
Quectel
Confidential
