User's Manual

HF-A21-SMT Embedded WiFi Module User Manual

Shanghai High-Flying Electronics Technology Co., Ltd

www.hi-flying.com

1.4. Software Reference Design

When HF-A21-SMT modules boot up phase, the general user board MCU software flow chart will

as following:

Figure 12. User MCU Software Flow Chart

When HF-A21-SMT modules boot up, user can select one work mode base on the setting, and

user can switch to the configuration mode at any kinds of work mode.

1.4.1. Transparent Transmission Mode

HF-A21-SMT modules support serial interface transparent transmission mode. The benefit of this

mode is achieves a plug and play serial data port, and reduces user complexity furthest. In this

mode, user should only configure the necessary parameters. After power on, module can

automatically connect to the default wireless network and server.

As in this mode, the module's serial port always work in the transparent transmission mode, so

users only need to think of it as a virtual serial cable, and send and receive data as using a

simple serial. In other words, the serial cable of users‟ original serial devices is directly replaced

with the module; user devices can be easy for wireless data transmission without any changes.

The transparent transmission mode can fully compatible with user‟s original software platform and

reduce the software development effort for integrate wireless data transmission.

Notes: Transparent transmission mode as a low level phy layer data transmitting can't keep zero

error rates by itself. User can enable UART port‟s hardware flow control CTS/RTS function or

though higher layer protocol such as TCP to lower error rate and mange the data completeness.

High-Flying recommend when doing large amounts of data transmitting in transparent

transmission mode, hardware flow control should be enabled, so as to fully ensure reliable data

transmission. In the applications which doesn‟t need flow control, users can simply leave RTS /

CTS pin vacant.

1.4.2. Configuration Mode

In configuration mode, user can finish HF-A21-SMT module configuration management and

parameters setting work. In work mode (Transparent Transmission), user can switch to the