Quectel BC66 - Recommended Stencil Design

NB-IoT Module Series
BC66 Hardware Design
BC66_Hardware_Design 28 / 59
Table 12: Pin Definition of UART Interfaces
When the module enters Light Sleep mode with a fixed baud rate, please send AT via UART to wake up
the module first before sending other AT commands.
3.9.1. 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 Deep Sleep 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.
Interface
Pin Name
Pin No.
Description
Comment
Main UART Port
TXD
17
Transmit data to RXD of DTE
1.8V power
domain
RXD
18
Receive data from TXD of DTE
Debug UART Port
RXD_DBG
38
Receive data from TXD of DTE
TXD_DBG
39
Transmit data to RXD of DTE
Auxiliary UART Port
RXD_AUX
28
Receive data from TXD of DTE
TXD_AUX
29
Transmit data to RXD of DTE
Ring Indication Signal
RI
20
Ring indication signal (when there is a
SMS or URC output, the module will
inform DTE with the RI pin)
NOTE