AN2262 Motorola / Freescale Semiconductor, AN2262 Datasheet - Page 9

• Manufacturer Part Number: AN2262
• Description: Wireless HC08 Modem
• Manufacturer: Motorola / Freescale Semiconductor

RS232 versus RS485
Configurations
MOTOROLA
On the other side, full-duplex operation (four-wire topology) enables
simultaneous communication in both directions. Thus, the transmitter and
receiver are enabled at all times. Jumper JP3 must be left open.
For proper operation of the current loop, each current loop has to be terminated
(i.e., effectively closing the current path back to the originating driver). Jumper
JP4 allows you to connect 120-
transmitting lines respectively.
Connect 1-2 to add 120
3-4 to add 120
For a detailed explanation of typical RS485 configurations refer to Maxim
Integrated Products MAX485 data sheet (
For RS232 configuration:
For RS485 configuration:
1. Maxim is a registered trademark of Maxim Integrated Products
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Populate: U6, C27, C28, C29, C30, and C37
Don’t populate: U5, C28, R25, and R28
Leave JP3 and JP4 open
Connect JP5 2-3
JP6 shorted if DSR to DTR connection required
RS485 half-duplex (two wires) configuration:
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–
–
–
–
–
RS485 full-duplex (four wires) configuration:
–
–
–
–
–
–
–
Populate: U5, C26, R25, and R28
Don’t populate: U6, C27, C28, C29, C30, and C37
Connect JP3 1-2, 3-4
Connect JP4 1-2 if 120-
Connect JP5 1-2
Leave JP6 open
Populate: U5, C26, R25, and R28
Don’t populate: U6, C27, C28, C29, C30, and C37
Leave JP3 open
Connect JP4 1-2 if 120-
Connect JP4 3-4 if 120-
Connect JP5 1-2
Leave JP6 open
Wireless HC08 Modem
between the RS485 receiving lines.
between the RS485 transmitting lines or connect
resistors between RS485 receiving and
load required, otherwise all open
TX load required (not usually)
RX load required (usually)
http://www.maxim-ic.com
Hardware Platform
).
AN2262/D
®(1)
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