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
DEBUG 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