Debug Interface - SimCom SIM800C Hardware Design

4.5.3

Debug Interface

SIM800C could achieve software debug function through USB interface. When powering on the module,
connect USB_VBUS, USB_DP, USB_DN, and GND to PC, then install the driver following the prompts, a
UART port could be recognized by PC, customer could achieve the software Debug with this UART port.
SIMCom recommended the following connected diagram:
The TVS on USB data line should be less than 5pF, and traced by differential forms.
Note: please reserve the USB interface or test point for the further debugging
Table 10: USB_VBUS operation voltage
SIM800C_Hardware_Design_V1.02
V D D _E X T
M odul e
4. 7K
V D D _E X T
47K
U A R T 1_T X D
Figure 21: TX level matching circuit
V D D _E X T
M odul e
V D D _E X T
4. 7K
U A R T 1_R X D
Figure 22: RX level matching circuit
U S B _V B U S
U S B _ D N
U S B _ D P
1uF
G N D
M O D U LE
Figure 23: USB reference circuit
D T E
V D D
4. 7K
R X D
D T E
V D D
4. 7K
47K
T X D
V B U S
22 R
U S B _ D N
22R
U S B _D P
G N D
U S B
27
Smart Machine Smart Decision
2015-4-27