Uart Interfaces - Quectel BC660K-GL Manual

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
Figure 10: Reference Design for BOOT Controlled with a Button
NOTE
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
Main UART Port
Debug UART Port
BC660K-GL_Hardware_Design
S1
TVS
Pin Name Pin No.
MAIN_TXD 17
MAIN_RXD 18
DBG_RXD 38
BOOT
Close to S1
Description
Main UART transmit
Main UART receive
Debug UART receive
NB-IoT Module Series
BC660K-GL Hardware Design
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