User's Manual

Wi-Fi&Bluetooth Module Series
FC905A_Hardware_Design 25 / 51
PCM
UART
FC905A
UART
PCM
HOST
BT_EN
BT_EN
GPIO1
HOST_WAKE_BT
GPIO2
BT_WAKE_HOST
Figure 5: Block Diagram of Bluetooth Application Interface Connection
3.6.1. UART Interface
FC905A supports an HCI UART as defined in Bluetooth Core Specification Version 5.1. The UART
supports hardware flow control, and it is used for data transmission with host. It supports up to 4.0 Mbps
baud rates.
Table 11: Pin Definition of UART Interface
The following figure shows a reference design for UART interface connection between FC905A and host.
Pin Name
Pin No.
I/O
Description
Comment
BT_RTS
41
DO
Bluetooth UART request to send
VIO power domain.
If unused, keep them open.
BT_TXD
42
DO
Bluetooth UART transmit
BT_RXD
43
DI
Bluetooth UART receive
BT_CTS
44
DI
Bluetooth UART clear to send