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H330S Hardware User Manual
Page 34 of 44
UART2
Pin#
Pin Name
I/O
Description
44
UART2_RXD
I
UART2 Received Data
45
UART2_TXD
O
UART2 Transmitted Data
5.5.2 UART Interface Application
Connect UART1 of H330S wireless module (DCE) to PC, and the signal direction of (DTE) is as follows:
MCU (DTE) application
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
Connect UART2 of H330S wireless module (DCE) to PC, and the signal direction of (DTE) is as follows:
MCU (DTE) application
Signal direction
H330S module (DCE)
RXD
UART2_TXD
TXD
UART2_RXD
Note
:
the high level of the module’s UART interface is 1.8V. If it needs to connect it to 2.8V or 3.3V IO
interface, it is necessary to switch the level.
In design: it is recommended to use SN74LVC2G07 to switch the level from 1.8V to 3.3V. During the
communication between UART1 and PC, firstly raise the level from 1.8V to 3.3V, and then, employ
SP3238 to switch the level. During the communication between UART2 and PC, firstly raise the level from
1.8V to 3.3V, and then, employ SPIEX3232EEA to switch the level. Pay attention to the signal direction
when switching the level.
