SimCom SIM800C, Проектирование аппаратного обеспечения

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Smart Machine Smart Decision
SIM800C_Hardware_Design_V1.02
19
2015-4-27
4.1.2. Monitoring Power Supply
AT command “AT+CBC” can be used to monitor the VBAT voltage. For detail, please refer to
document [1]
.
4.2. Power on/off SIM800C
4.2.1. Power on SIM800C
Customer can power on SIM800C by pulling down the PWRKEY pin for at least 1 second and release. This pin
is already pulled up to VBAT in the module internal, so external pull up is not necessary. Reference circuits are
shown as below.
4.7K
47K
T urn on/off
im pulse
P W R K E Y
P ow er
on/off logic
100K
3V
M odule
1K
Figure 10: Powered on/down module using transistor
P W R K E Y P ow er
on/off logic
100K
3V
M odule
1K
Figure 11: Powered on/down module using button
The power on timing is illustrated as in the following figure.
V
IL
<0.7V
U ndefind
A ctive
V B A T
P W R K E Y
(IN P U T )
t>3s
V D D _E X T
S T A T U S
t>1s
S erial P ort
T >1.5s
T >55m s
Figure 12: Timing of power on module