Quectel BC660K-GL - UART Interfaces; Main UART Port; Debug UART Port

NB-IoT Module Series
BC660K-GL Hardware Design
BC660K-GL_Hardware_Design 26 / 57
In the process of module reset or powering on, drive and keep the BOOT pin low and the module will
enter the download mode.
In the download mode, the firmware can be downloaded through the main serial port. After the download
is completed, the module needs to be reset to exit from the download mode.
A reference design is shown below
BOOT
S1
Close to S1
TVS
Figure 10: Reference Design for BOOT Controlled with a Button
If the BOOT pin is connected to a filter capacitor in parallel, the capacitance of the capacitor cannot be
higher than 33 pF.
3.7. UART Interfaces
The module provides two UART ports: the main UART port and the debug UART port. The module is
designed as DCE (Data Communication Equipment), following the traditional DCE-DTE (Data Terminal
Equipment) connection.
Table 11: Pin Definition of UART Interfaces
Interface
Pin Name
Pin No.
Description
Main UART Port
MAIN_TXD
17
Main UART transmit
MAIN_RXD
18
Main UART receive
Debug UART Port
DBG_RXD
38
Debug UART receive
NOTE