A customizable TP-UART interface
The release package includes software for the MSP430 that works around one timing constraint of the TP-UART host protocol (end-of-packet detection) and monitors another (U_AckInformation timeout). The paper "Design of an enhanced TP-UART based KNX PC interface" contains detailed background information. Note the following addendum regarding U_AckInformation service timing:
Figure 6 in this paper not only shows the latest point in time for the host controller to send the U_AckInformation-Service, but also includes an "earliest" point. While "latest" is discussed in depth, it remains unclear what "earliest" refers to.
This "earliest" point in time is actually the earliest point in time that we tested. Theoretically, the TP-UART might accept the U_AckInformation-Service already a little earlier than that (maybe once it has completely received the control field); however, we did not test this.
There definitely and necessarily is a state in which U-AckInformation-Services are ignored by the TP-UART. Otherwise, a U-AckInformation that was sent too late would be applied to the next frame on the medium.
In addition, the release package includes a simple demo program that operates the TP-UART in analog mode. It transmits a KNX standard data frame once upon reset. The frame is statically defined and there is no medium access control. The program can easily be modified to generate faulty frames (e.g., with a bad check octet) for test purposes.
Martin Kögler has provided a patch for the eibd TP-UART backend that allows eibd to make use of the end-of-packet signalization (Break variant) provided by ACTIface.
If you have written firmware or host side software for ACTIface and are willing to share it, we will be happy to mention and/or host it here!
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