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SIM800H _Hardware Design_V2.03
44
2016-10-10
4.13.
ADC
Table 25: Pin definition of the ADC
SIM800H provides an auxiliary ADC, which can be used to measure the voltage. Customer can use AT command
“AT+CADC” to read the voltage value. For details of this AT command, please refer to
document [1]
.
Table 26: 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
4.14.
PWM
Table 27: Pin definition of the PWM
SIM800H provides a PWM which can be used to drive a vibrator, and a backlight LED for display or keyboard.
PWM output frequency varies from 0~2kHz. Two 7-bit unsigned binary parameters are used for the output period
and for the duty cycle. AT command “AT + SPWM” is used to set the output period and duty cycle of the PWM.
For details, please refer to
document [1]
.
A typical recommended circuit of the PWM driver buzzer is shown in the following figure.
4.7K
47K
VBAT
Module
PWM
Figure 42: Reference circuit of PWM driver buzzer
Pin name
Pin number
Description
ADC
50
Analog voltage input
Pin name
Pin number
Description
PWM
26
PWM signal
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