H330SS LGA Module Hardware User Manual Page 28 of 38
5.5.2
UART Design
The following table show the signal direction when H330S wireless communication module (DCE) UART1
connects to PC (DTE):
Application MCU(DTE)
Signal Direction
H330S Module (DCE)
RXD
UART1_TXD
TXD
UART1_RXD
RTS
UART1_CTS
CTS
UART1_RTS
DSR
UART1_DTR
DTR
UART1_DSR
RI
UART1_RI
DCD
UART1_DCD
The following table shows the signal direction when H330S wireless communication module (DCE) UART2
connects to PC (DTE):
Application MCU(DTE)
Signal Direction
H330S Module (DCE)
RXD
UART2_TXD
TXD
UART2_RXD
Note: H330S wireless communication module UART high level is 1.8V, please use external level shifter if connect
to 2.8V or 3.3V IO interface.
When design:
Level shift from 1.8V to 3.3V, SN74LVC2G07 is recommended.
When UART1 communicating with PC, first shift from 1.8V to 3.3V, and then uses SP3238 to shift.
When UART2 communicating with PC, first shift from 1.8V to 3.3V, and then uses SPIEX3232EEA to shift level.
Notice the signal direction when shift level.