M20 Hardware Design
GND
C4
GND C5
VPP C6 Not
connect
SIM_DATA
C7
SIM Card data I/O
SIM_PRESENCE
C8
SIM Card Presence detection
3.12 ADC
The pin ADC1 can be used to measure analog voltage. Customer can get the measurement result
through AT command “AT+QEADC”.
Table 23: Pin definition of the ADC
Name
Pin
Function
ADC1 12
Measure
analog
voltage
Table 24: Characteristics of the ADC
Min
Typ
Max
Units
Voltage range
0
2.8
V
ADC Resolution
10
10
bits
ADC accuracy
2.7
mV
3.13 Behavior of the pin RI0
Table 25: Behaviours of the RI0
State
RI respond
Standby HIGH
Voice calling
Change to LOW, then:
（
1
）
Change to HIGH when call is established.
（
2
）
Use ATH to hang up the call, change to HIGH.
（
3
）
Calling part hangs up, change to HIGH.
(4) Change to HIGH when SMS is received.
Data calling
Change to LOW, then
：
（
1
）
Change to HIGH when data connection is established.
（
2
）
Use ATH to hang up the call, change to HIGH.
SMS
When a new SMS comes, The RI changes to LOW and holds low level for
about 120 ms, then changes to HIGH.
URC
Certain URCs can trigger 120ms low level on RI. For more details, please
refer to the
document [10]
M20_HD_V1.01
- 59 -
Quectel
