Smart Module Series
SC206E_Series_Hardware_Design 46 / 115
UART0 is a four-wire UART interface with 1.8 V power domain. You should use a level translator if your
application is equipped with a 3.3 V UART interface. The following figure shows a reference design.
VCCA
VCCB
OE
A1
A2
A3
A4
GND
B1
B2
B3
B4
LDO15A_1V8
UART0_RTS
UART0_RXD
UART0_CTS
UART0_TXD
RTS_3.3V
RXD_3.3V
CTS_3.3V
TXD_3.3V
VDD_3.3V
C1
100 pF
C2
U1
100 pF
Figure 13: Reference Circuit with Level Translator Chip for UART0
The following figure presents an example of connection between the module and a PC. It is
recommended to add a level translator and an RS-232 level translator chip between the module and the
PC.
RTS_3.3V
RXD_3.3V
CTS_3.3V
TXD_3.3V
RTS_1.8V
RXD_1.8V
CTS_1.8V
TXD_1.8V
VCCA
Module
GND
GND
1.8 V
VCCB
3.3 V
DIN1
ROUT3
ROUT2
ROUT1
DIN4
DIN3
DIN2
DIN5
R1OUTB
FORCEON
/FORCEOFF
/INVALID
3.3 V
DOUT1
DOUT2
DOUT3
DOUT4
DOUT5
RIN3
RIN2
RIN1
VCC
GND
OE
DB-9
RTS
TXD
CTS
RXD
GND
UART0_RXD
UART0_TXD
UART0_RTS
UART0_CTS
Figure 14: RS-232 Level Match Circuit for UART0
UART0_RTS
37
DO
DCE request to send signal to DTE
UART0_CTS
36
DI
DCE clear to send signal from DTE
DBG_TXD
94
DO
Debug UART transmit
DBG_RXD
93
DI
Debug UART receive
UART1_TXD
154
DO
UART1 transmit
UART1_RXD
153
DI
UART1 receive