Data Sheet

10. Connection Examples
The following sections show how to connect the BT122 Dual Mode Module with various external devices using the UART and I
2
C inter-
face.
10.1 Connecting an External Host Using the UART Interface
The connection to an external host is done using the UART interface of the module. This interface is also used for module reprogram-
ming using the DFU method, and, therefore, an optional connector should be provided on the application PCB to allow reprogramming
if needed. A typical solution then is to hold the host in reset state which will keep the UART pins of the host floating, allowing the inter-
face to be used for programming the module by using, for example, a PC and suitable software. See the figure below.
1
2
3
4
5
6
7
8
20
19
18
17
16
15
14
13
9
10 11 12
GND
GND
GND
GND
GND
GND
GND GND
TOP VIEWPA 0
PA 1
PC8
PC9
VDD
RESET
PF0
PF1
PF2 PF3 PF4 PF5
HOST
UART
RX
TX
RTS
CTS
VDD
VSS
RESET
CTS
RTS
TX
RX
BT122
UART
GND
RX
TX
RTS CTS
RST
VDD
3V3
BT122
EXTERNAL HOST
MICROPROCESSOR
OPTIONAL CONNECTOR ON APPLICATION PCB
ALLOWS CONTROL AND REFLASH OF MODULE
FOR EXAMPLE FROM A PC
3V3
3V3
Figure 10.1. Connecting an External Host with BT122 Using UART
BT122 Data Sheet
Connection Examples
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