NB-IoT Module Series
BC66 Hardware Design
BC66_Hardware_Design 26 / 50
TXD
RXD
TXD
RXD
Module (DCE)
Serial port
Main port
GND
GND
DTE
Figure 12: Reference Design for Main UART Port
3.8.2. Debug UART Port
Through log viewer tools, customers can check the log information via debug UART port for firmware
debugging. A reference design for the debug UART port is shown below.
DTE
TXD
RXD
GND
Module
TXD_DBG
RXD_DBG
GND
Figure 13: Reference Design for Debug UART Port
3.8.3. Auxiliary UART Port
The auxiliary UART port is used for AT command communication and data transmission. A reference
design for the auxiliary UART port is shown below.