User's Manual

HF-A21-SMT Embedded WiFi Module User Manual
Shanghai High-Flying Electronics Technology Co., Ltd
www.hi-flying.com
37
4. AT+INSTRUCTION INTRODUCTION
4.1. Configuration Mode
When HF-A21-SMT power up, it will default works as transparent transmission mode, then user
can switch to configuration mode by serial port command. HF-A21-SMT UART default
parameters setting as below figure,
Figure 38. HF-A21-SMT Default UART Port Parameters
In configuration mode, user can setting the module through AT+ instruction set, which cover all
web page setting function.
4.1.1. Switch to Configuration Mode
Two steps to finish switching from transparent transmission mode to configuration mode.
 UART input “+++”, after module receive “+++”, and feedback “a” as confirmation.
 UART input “a”, after module receive “a” and feedback “+ok” to go into AT+
instruction set configuration mode.
Figure 39. Switch to Configuration Mode
Notes:
1. When user input “+++” (No “Enter” key required), the UART port will display feedback
information “a”, and not display input information”+++” as above UART display.
2. Any other input or wrong step to UART port will cause the module still works as original mode
(transparent transmission).