
Smart Machine Smart Decision
SIM5800_Hardware Design_V1.01
30
2018-10-08
+
10K NTC
AUXADC_REF
BAT_ID
PMU
VBAT
Module
Battery
R2
1K±1%
R1
16.9K±1%
GND
VBAT
R3
27K±1%
Figure 20: BAT_ID diagram
4.7
UARTs
SIM5800 provides two UARTs
,
the pin definition is in the following table
:
Table 7: UART pins definition
If the voltage of UART is 3.3V, customer can use the following reference circuits:
VIO18_PMU
4.7K
47K
TXD
4.7K
Module
VIO18_PMU
RXD
VDD
Customer
Figure 21: TX level converting by transistor
Name
Pin
I/O
Function
UART1_TXD 34
O
UART1 Transmit data
UART1_RXD 35
I
UART1 Receive data
UART1_CTS
36
I
UART1 Clear to send
UART1_RTS
37
O
UART1 Request to send
UART2_TXD 173
O
UART2 Transmit data
UART2_RXD 174
I
UART2 Receive data