NB-IoT Module Series
BC66 Hardware Design
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VBAT
20ms
Resetting
Module
Status
Running
RESET
Restart
≥
50ms
VDD_EXT
············
Figure 13: Reset Timing
3.8. UART Interfaces
The module provides three UART ports: main UART port, debug UART port and auxiliary UART port. The
module is designed as DCE (Data Communication Equipment), following the traditional DCE-DTE (Data
Terminal Equipment) connection.
Table 9: Pin Definition of UART Interfaces
Interface
Pin Name Pin No.
Description
Comment
Main UART Port
TXD
17
Send data to RXD of DTE
1.8V power
domain
RXD
18
Receive data from TXD of DTE
Debug UART Port
RXD_DBG
38
Send data to RXD of DTE
TXD_DBG
39
Receive data from TXD of DTE
Auxiliary UART Port
RXD_AUX
28
Send data to RXD of DTE
TXD_AUX
29
Receive data from TXD of DTE
Ringing Signal
RI*
20
Ring indicator (when there is a SMS
or URC output, the module will inform
DTE with the RI* pin)
