Signal Charts For The Rts/Cts Procedure; Data Input - Siemens SINUMERIK 840 Planning Manual

06.91
3.3.4.1

Signal charts for the RTS/CTS procedure

3.3.4.1.1

Data input

DTR
DSR
CTS
RTS
RxD
TxD
After initializing (activating) the interface, DTR changes to 1.
The pin assignments refer to the receiver shown in the figure of Section 3.3.4.
After initializing the interface, the DTR control line is activated. The "Data start" command
enables the procedure driver to activate the RTS control line (priority = slave). The CP is
ready to receive from this instant, i.e. the receiving scratch is enabled.
As soon as the receiving scratch is full but no new scratch is available, the driver deactivates
the RTS. The output system must then stop transmitting. After clearing and/or after enabling
the receiving scratch, RTS is again activated and the CP can continue reading of the data.
After deactivating the RTS procedure, the receiving node is still able to buffer up to ten
characters.
If a new receiving scratch is available, the characters are copied into this scratch and RTS
reactivated.
Transmitting jobs can also be processed in parallel to this job.
© Siemens AG 1989 All Rights Reserved
SINUMERIK 840/880 (PJ)
Ready to receive Not
ready to receive
6FC5 197-0AB20-0BP0
3 Interface Modules
3.3.4 RTS-LINE (RTS/CTS)
Ready to receive Not
ready to receive
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