AN210: SP336 Pinout Recommendation for Single DB

AN210: SP336 Pinout Recommendation for Single DB
APPLICATION NOTE
AN210
SP336 PINOUT RECOMMENDATION FOR SINGLE DB-9 CONNECTOR
1.0 INTRODUCTION
This document provides recommendations on how the SP336 can be used to support RS-232, half-duplex RS485, and full-duplex RS-485/RS-422 on a single DB-9 connector.
2.0 RS-232 PINOUT
Figure 1 below shows the signals from the UART that are connected to the SP336. For RS-232, the DB-9 pins
are defined. Since there are only 4 receivers on the SP336, the DSR signal from the DB-9 connector is not
shown in the drawing. However, DSR can replace any of the other UART inputs that are not used.
FIGURE 1. RS-232 PINOUT
1
APPLICATION NOTE
AN210
3.0 FULL-DUPLEX RS-485/RS-422 PINOUT
Figure 2 below shows which pins the full-duplex RS-485/RS-422 signals will be on the DB-9 connector when
using the same UART connections shown in Figure 1. The RTS pin from the UART can be used to enable/
disable the differential driver outputs.
FIGURE 2. FULL-DUPLEX RS-485/RS-422 PINOUT
2
APPLICATION NOTE
AN210
4.0 HALF-DUPLEX RS-485 PINOUT
Figure 3 below shows the half-duplex RS-485 connections. The RTS pin is used to control the direction of the
RS-485 differential drivers and receivers.
FIGURE 3. HALF-DUPLEX RS-485 PINOUT
5.0 SUMMARY
The tables below summarize the configurations in this document. Table 1 shows what the pin signals will be at
the DB-9 connector.
TABLE 1: DB-9 CONNECTOR PIN CONNECTIONS
RS-232 Mode
DB-9
PIN 1
DB-9
PIN 2
DB-9
PIN 3
DB-9
PIN 4
DB-9
PIN 5
DCD
RxD
TxD
DTR
RX+
RS-485/RS-422 Mode
(Full-Duplex)
RS-485 Mode
(Half-Duplex)
SP336 Pin Number
17
15
DB-9
PIN 7
DB-9
PIN 8
DB-9
PIN 9
GND
RTS
CTS
RI
TX+
GND
TX-
RX-
DATA+
GND
DATA-
8
7
6
4
3
DB-9
PIN 6
16
18
APPLICATION NOTE
AN210
Table 2 shows the same information as table 1 but presented in a different way.
TABLE 2: SP336 PIN CONNECTIONS
SP336
PIN 4
SP336
PIN 6
SP336
PIN 7
SP336
PIN 8
SP336
PIN 15
SP336
PIN 16
SP336
PIN 17
SP336
PIN 18
DTR
TxD
RTS
GND
RxD
CTS
DCD
RI
RS-485/RS-422 Mode
(Full-Duplex)
TX+
TX-
GND
RX+
RX-
RS-485 Mode
(Half-Duplex)
DATA+
DATA-
GND
3
7
5
2
8
1
9
RS-232 Mode
DB-9 Pin Number
4
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to
improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any
circuits described herein, conveys no license under any patent or other right, and makes no representation that
the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration
purposes and may vary depending upon a user’s specific application. While the information in this publication
has been carefully checked; no responsibility, however, is assumed for inaccuracies.
EXAR Corporation does not recommend the use of any of its products in life support applications where the
failure or malfunction of the product can reasonably be expected to cause failure of the life support system or
to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless
EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has
been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately
protected under the circumstances.
Copyright 2011 EXAR Corporation
Document January 2011.
For technical support please email Exar’s Serial Technical Support group at: [email protected]
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
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