9-Bit Framing Serial Communication

Transfering 9-Bit serial data frames

9-Bit framing serial communication is mainly used to identify address byte within messages running on a RS-485 multidrop network but also on standard RS-232 connections. On a RS-485 network usually a master (PC) controls one or many clients (e.g. micro controllers).

The PC working as master polls on one or more clients but always one client at a time. Once the client controller receives a request starting with it's 9-bit address it replys accordingly. That is 9-bit data frames on a RS-485 network.

9-Bit frames are usually not supported by the standard PC UART but simulated by the SuperCom software (Windows and Linux). Very fast response timing (low latency) by the software is essential to accomplish reliable 9-bit data communication. SuperCom does provide a very realiable solution here to be used with high level languages.

Many Samples (e.g. C/C++, C#, Delphi) also included in SuperCom serial library that demonstrate this operating mode.

For example, transmitting a data packet using 9-bit addressing e.g.:

        TXPacket9BitCond(Com, cData, nDataCount, SEC0_1);

The DEMO software found online, even when activating RS-485, are working with limited functionality, especially when it comes to response timing. The complete functionality is contained only in the licensed version.

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