User`s manual

Odriver specifies RS-422/485 output driver enable option for theDSP-200/300. The
DSP-200/300’s port may be configured for either full duplex or half duplex
operation with this option. If this option is omitted, the default setting is the
RS-422/485 port is configured for full duplex operation with the RS-422/485
output drivers always enabled. In half duplex mode, the RS-422/485
transmitter may be enabled and disabled via the RTS (request to send) or
DTR (data terminal ready) signals. Both RTS and DTR are controlled
through the Modem Control Register of the 16750. See the Hardware
Information section for more information.
Auto-toggleo3
RTS Controlledo2
DTR Controlledo1
Always Enabledo0
Output DriverOption
Figure 4. DOS Enabler Output Enable Options.
2-13 DSP-200/300 (Rev. I and later) User's Manual
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