MOD-RS485 development board
Users Manual
All boards produced by Olimex are ROHS compliant
Revision Initial, April 2011
Copyright(c) 2011, OLIMEX Ltd, All rights reserved
Page 1
INTRODUCTION:
MOD-RS485 is a small module board realized with ADM3483ARZ - low
power, differential line transceiver designed to operate using a single 3.3 V power
supply, for half-duplex communication. This module can be used to convert RS232
signals into RS485 signals. The board comes with 10 pin cable for the UEXT, via
which it can be connected to each of our development boards with UEXT on it.
This module is an excellent choice for conveying information over long dis-
tances, allowing error-free data transmission at data rates up to 250 kbps.
BOARD FEATURES:
•
•
•
•
•
Half-duplex transceiver ADM3483ARZ from Analog Devices
UEXT connector
RS485 connector
FR-4, 1.5 mm, soldermask, component print
Dimensions: 30.99x20.32mm (1.22 x 0.80")
ELECTROSTATIC WARNING:
The
MOD-RS485
board is shipped in protective anti-static packaging. The board
must not be subject to high electrostatic potentials. General practice for working
with static sensitive devices should be applied when working with this board.
BOARD USE REQUIREMENTS:
Cables:
The board comes with 10 pin cable for the UEXT connector.
Hardware:
Any of our development boards wit UEXT connector on it.
Page 2
FUNCTIONAL BLOCK DIAGRAM:
Page 3
SCHEMATIC:
3.3V
C1
100nF
+
C2
2
3.3V
3.3V
3.3V
47uF/6.3V/tant
0
1
ENABLE_RT
R1
NA
R5
NA
UEXT
1
2
3
4
RO
/RE
DE
DI
VCC
B
A
GND
8
7
6
5
U1
RT
120R
R2
NA
TXD
SCL
ADM3483ARZ
1
2
Page 4
#SS/SDA
R3
NA
SCK
1
3
5
7
9
2
4
6
8
10
RXD
SDA
B
A
R6
NA
#SS
TB4/5MM
RS485-4
RS485-3
RS485-2
RS485-1
3.3V
R4
100R
BH10S
#ss
3
sck
3
2
1
SCL/SCK
MOD-RS485
Rev. Initial
COPYRIGHT(C) 2010, OLIMEX Ltd.
http://www.olimex.com/dev
BOARD LAYOUT:
POWER SUPPLY CIRCUIT:
MOD-RS485
is power supplied via UEXT connector pin 1 (3.3V) and pin 2 (GND).
JUMPER DESCRIPTION:
ENABLE_RT
This jumper, when closed, enables 120 Ohm termination on the RS485 bus.
Default state is closed.
SCL/SCK
This jumper, when is in position SCL – connects UEXT pin 5 (SCL) to ADM3483ARZ
pin 3 (DE) and when is in position SCK – connects UEXT pin 9 (SCK) to
ADM3483ARZ pin 3 (DE).
Default state is in position SCK.
#SS/SDA
This jumper, when is in position #SS – connects UEXT pin 10 (#SS) to ADM3483ARZ
pin 2 (/RE) and when is in position SDA – connects UEXT pin 6 (SDA) to
ADM3483ARZ pin 2 (/RE).
Default state is in position #SS.
Page 5
