User's Manual

HF-A21-SMT Embedded WiFi Module User Manual
Shanghai High-Flying Electronics Technology Co., Ltd
www.hi-flying.com
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HF-A21-SMT‟s default interval time is 50ms. User can also set this interval to fast (10ms) through
AT command. But user have to consider if user MCU can send UART data with 10ms interval ,or
the UART data may be divide as fragment.
Through AT command: AT+FUARTTE=fash/normal, user can set the interval time: fast (10ms)
and normal (50ms). This command is factory default setting command and AT+RELD can‟t
change its value.
2.4.2. UART Auto-Frame
HF-A21-SMT support UART auto-frame function. If user select open this function and setting
auto-frame trigger length and auto-frame trigger time parameters, then module will auto framing
the data which received from UART port and transmitting to the network as pre-defined data
structure.
 Auto-frame trigger length: The fixed data length that module used to transmitting to
the network.
 Auto-frame trigger time: After the trigger time, if UART port received data can‟t reach
auto-frame trigger length, then module will transmitting available data to the network
and bypass the auto-frame trigger length condition.
Detailed UART auto-frame function can refer to AT+ instruction set “UARTF/UARTFT/UARTFL”
introduction.
2.5. Address Binding
HF-A21-SMT module supports the feature of binding the BSSID address of target network.
According to the provisions of 802.11 protocol, different wireless networks can have a same
network name (i.e. SSID / ESSID), but must correspond to a unique BSSID address (i.e. MAC
address). Illegal intruders can create a wireless network with the same SSID / ESSID, it will make
STAs in the network to join to the illegal AP, thereby and then network leakage happen.
Users can prevent STA from joining to illegal network by binding the BSSID address, to improve
wireless network security.
2.6. Ethernet Interface Communication
HF-A21-SMT module provides one 10/100M Ethernet interface. With this Ethernet interface, user
can easily realize the three interface (WiFi, UART, and Ethernet) intercommunication and
networking. HF-A21-SMT module can configured as Bridge Mode or Router Mode base on
different networking technology.
Notes: The Ethenet function is disabled by default because of the large power consumption.
Users may input “AT+FEPHY=on” and reset to enable Ethenet. HF-A21-SMT need different
configuration to support different Ethenet Networking mode (Such as “N-Ver” and “Z-Ver” as
following, which need AT+FVER=n to switch to N-Ver or AT+FVER=z to switch to Z-Ver).
2.6.1. HF-A21-SMT Ethernet Interface Networking (As AP)
Figure 18. HF-A21-SMT Ethernet Interface Networking (As AP)