Uarts - Sunsea AIoT SIMCom SIM5800 Hardware Design

4.7

UARTs

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