HF-A11 Embedded WiFi Module User Manual
Shanghai High-Flying Electronics Technology Co., Ltd
www.hi-flying.com
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1.3.2.1. Ethernet Connection with Transformer
User board put Ethernet transformer and RJ-45 connector. This is a general 10/100M Ethernet
phy layer connection. The reference design as following:
Figure 9.
Ethernet Reference Design with Transformer
1.3.2.2. Ethernet Connection without Transformer
For this application, Ethernet will work as internal data transmition interface and save one
transformer and RJ-45 connector. Ethernet PHY-to-PHY connection will use AC coupled
connection. This is a space and cost optimized solution. Hardware reference design as following:
Note: VCC signal at reference design shall base on user board PHY chipset voltage level, such
as 2.5V power supply for general Ethernet PHY chipset.
Figure 10. Ethernet Reference Design without Transformer
1.3.3. UART
Interface
UART interface is the serial data transmition interface mainly used for HF-A11 modules.
User can add RS-232 chipset on user board and convert the signal to RS-232 voltage to
communicate with outside equipment or sensors. HF-A11 modules UART interface include 4
general signals: TXD/RXD/RTS/CTS. The hardware reference design with RS-232 chipset as
following:
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