User's Manual

HF-A21 Embedded WiFi Module User Manual
Shanghai High-Flying Electronics Technology Co., Ltd
www.hi-flying.com
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nReady- Module boot up ready signal. Output. Logics “0” effective.
There is 4.7K Ohm pull-up resister internal. The module will output “0” “or “Palmodic Signal” after
normal boot up. This signal used to judge if module finish boot up and ready for application or
working at normal mode.
nLink- Module WIFI connection indication. Output.
There is 4.7K Ohm pull-up resister internal. When module connect to AP (STA mode) or some
WiFi STA connect to module (AP mode), the module will output “0”. This signal used to judge if
module already at WiFi connection status.
nReload- Module restore to factory default configuration.Input. Logics “0” effective.
User can assert nReload signal “0” more than 3’s through button or MCU pin, then release,
module will restore to factory default configuration and re-start boot up process. User need add
4.7K~10K Ohm pull-up resister external the module. If not use this function, then can use AT
command AT+FRLDEN=off to disable it.
UART_TXD/RXD- UART port data transmit and receive signal.
1.4. Typical Application
Refer to HF-A21-SMT user manual for detailed application and module usage.