User's Manual

Wi-Fi&Bluetooth Module Series
FC41D_Hardware_Design
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The reset timing is illustrated in the following figure.
V
IL
 0.5 V
V
IH
 2.4 V
VBAT
CEN
T  100 ms
Figure 5: Timing of Resetting Module
3.6. Wireless Connection Interfaces
3.6.1. UART
The module has two serial interfaces: the main UART and the debug UART. The module is used as DCE
(Data Communication Equipment), and is connected in the traditional DCE-DTE (Data Terminal
Equipment) mode.
Table 7: UART Pin Definition
The main UART can be used for AT command transmission and data transmission. The default baud
rate is 115200 bps, and the maximum baud rate can reach 921600 bps. For more details, see document
[1].
The main UART is available for firmware upgrade and supports a default baud rate of 921600 bps when
download.
The following diagram shows a schematic diagram of the main UART interface connection between DCE
and DTE.
Interface
Pin Name
Pin No.
Description
Main UART
MAIN_TXD
20
Main UART transmit
MAIN_RXD
19
Main UART receive
Debug UART
DBG_TXD
26
Debug UART transmit
DBG_RXD
25
Debug UART receive