Specifications

Chapter 5 - Software RS-422 And RS-485 Applications Ebook
Page 67 of 137 Manual Documentation Number: <DocNumber>
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Under some operating systems (Windows) it can be difficult to release
RTS in a timely manner and this method of driver control should be
avoided altogether.
Figure 49: RS-485 RTS Driver Control
Another method of RS-485 driver control is Automatic Send Data
Control. Internal circuitry senses when data is being transmitted and
automatically enables the driver. It must then disable the driver within
one character length of the end of transmission. This is the preferred
method of driver control since it reduces software overhead and the
number of potential pitfalls for the programmer.
Figure 50: Automatic Send Data Driver Control
Other methods, such as bit-wise enable timing and auto-bauding may
also be used in certain situations. Refer to the section on Tri-State
Control (on page 16) earlier in this document.