SP336E Datasheet, PDF (26/30 Pages) Exar Corporation – 3.3V - 5V PROGRAMMABLE RS-232/RS-485/RS-422 SERIAL TRANSCEIVER

SP336E
3.3V - 5V PROGRAMMABLE RS-232/RS-485/RS-422 SERIAL TRANSCEIVER
REV. 1.0.0
Bus Repeater
Mode 101 can be used as a bus-repeater to extend the reach of an RS-422 bus. This configuration is best
suited for point-to-point or multi-drop communications because the drivers are always active and echoing data
from their corresponding receiver.
For applications where multiple nodes are allowed to transmit, some type of bus arbitration should be used.
One technique would be to use SP336E in conjunction with external decoder logic, packet buffers and node
address fields embedded in the data stream. Receiving the correct node address triggers Tx_EN to pass data
onward.
Mode 100 could implement a repeater / gateway to partition or extend RS-485 networks. Direction Control
determines when data is forwarded to or from segments A and B.
FIGURE 27. RS-422 BUS-REPEATER (MODE 101)
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