Product Info

Smart LTE Module Series
SC66 Hardware Design
SC66_Hardware_Design 59 / 139
UART6 is a 4-wire UART interface with 1.8V power domain. A level translator chip should be used if
customers’ application is equipped with a 3.3V UART interface. A level translator chip TXS0104EPWR
provided by Texas Instruments is recommended.
The following figure shows a reference design.
VCCA
VCCB
OE
A1
A2
A3
A4
GND
B1
B2
B3
B4
LDO11A_1P8
UART
6_ RTS
UART6_ RXD
UART
6_ CTS
UART6_ TXD
RXD_3.3V
CTS_3.3V
TXD_3.3V
VDD_3.3V
TXS0104EPWR
C1
100pF
C2
U1
100
pF
RTS_3.3V
Figure 17: Reference Circuit with Level Translator Chip (for UART6)
The following figure is an example of connection between SC66 and PC. A voltage level translator and a
RS-232 level translator chip are recommended to be added between the module and PC, as shown
below:
data
DEBUG_RXD 6 DI
DEB
UG UART receive
data
1.8 power domain.
UART1_TXD 7 DO UART1 transmit data 1.8 power domain.
UART1_RXD 8 DI UART1 receive data 1.8 power domain.
UART6_RXD 198 DI UART6 receive data 1.8 power domain.
UART6_TXD 199 DO UART6 transmit data 1.8 power domain.
UART6_CTS 246 DI UART6 clear to send 1.8 power domain.
UART6_RTS 245 DO UART6 request to send 1.8 power domain.
LPI_UART_2_
TXD
60 DO
LPI_UART_2
transmit data
1.8 power domain.
Cannot be multiplexed into
general-purpose GPIOs..
LPI_UART_2_
RXD
61 DI
LPI_UART_2
receive data