Smart Machine Smart Decision
SIM800_Hardware Design_V1.10
45
2018-08-13
PWRKEY
(INPUT)
GPIO17
t<1.9s
GPIO19
t<=10us
t<1.9s
Figure 41: GPIO timing sequences
4.14.
ADC
Table 23: Pin definition of the ADC
SIM800 provides an auxiliary ADC, which can be used to measure the voltage. Customerr can use AT command
“AT+CADC” to read the voltage value. For details of this AT command, please refer to
document [1].
Table 24: ADC specification
Parameter
Min
Typ
Max
Unit
Voltage range
0
-
2.8
V
ADC Resolution
-
10
-
bits
Sampling rate
-
-
1.0833
MHz
ADC precision
10
30
mV
Note: the voltage should less than 2.8V, or the ADC may be damaged.
4.15.
PWM
Table 25: Pin definition of the PWM
Note: SIM800 can only support 1 PWM synchronously, if customer set PIN 35 as PWM, so PIN36 can only be
used as GPIO.
PWM output frequency varies from 200Hz – 100KHz.Two 7-bit unsigned binary parameters are used for the
Pin name
Pin number
Description
ADC
25
Analog to Digital Converter
Pin name
Pin number
Description
PWM0
35
PWM0
PWM1
36
PWM1
