Main Uart Port; Debug Uart Port - Quectel BC66 Hardware Design

NOTE
"*" means under development.

3.8.1. Main UART Port

The main UART port supports AT command communication, data transmission and firmware upgrade.

By default, the module is in auto-baud mode and it supports automatic baud rates not exceeding
115200bps. When powering on the module, the MCU has to send AT command consecutively to
synchronize baud rate with the module. When OK is returned, it indicates the baud rate has been
synchronized successfully. When the module is woken up from PSM or idle mode, the baud rate
synchronized during start-up will be used directly.

When the port is used for firmware upgrade, the baud rate is 921600bps by default.
The figure below shows the connection between DCE and DTE.

3.8.2. Debug UART Port

Through debug tools, the debug UART port can be used to output logs for firmware debugging. Its baud
rate is 115200bps by default. The following is a reference design of debug UART port.
BC66_Hardware_Design
Module (DCE)
Main port
TXD
RXD
GND
Figure 14: Reference Design for Main UART Port
NB-IoT Module Series
BC66 Hardware Design
DTE
Serial port
TXD
RXD
GND
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