Smart Module Series
SC200K_Series_Hardware_Design 46 / 105
Table 12: Pin Definition of UART Interfaces
The three UART interfaces of the module are 1.85 V. A level translator chip should be used if the module
connects with a 3.3 V UART interface. A level translator TXS0104EPWR provided by Texas Instruments
is recommended. The following figure shows a corresponding reference design.
VCCA
VCCB
OE
A1
A2
A3
A4
GND
B1
B2
B3
B4
VDD1V85
UART0_RTS
UART0_RXD
UART0_CTS
UART0_TXD
RTS_3.3V
RXD_3.3V
CTS_3.3V
TXD_3.3V
VDD_3.3V
TXS0104EPWR
C1
100 pF
C2
U1
100 pF
Figure 16: Reference Circuit of Level Translator Chip (For UART0)
When the module communicates with PC, level translation is also required. A level translator chip and an
RS-232 translator chip are recommended to be added. The following figure shows a corresponding
reference design.
Pin Name
Pin No.
I/O
Description
Comment
DBG_TXD
94
DO
Debug UART transmit
1.85 V power domain.
If unused, keep it open.
Dot not pull DBG_TXD
down when turning on the
module.
DBG_RXD
93
DI
Debug UART receive
1.85 V power domain.
If unused, keep it open.
UART0_TXD
34
DO
UART0 transmit
UART0_RXD
35
DI
UART0 receive
UART0_CTS
36
DI
DCE clear to send
UART0_RTS
37
DO
DCE request to send
UART2_TXD
154
DO
UART2 transmit
UART2_RXD
153
DI
UART2 receive
