Evaluation Board Configuration; Setting Up The Evaluation Board; Input/Output Connections - Analog Devices EVAL-RS485HDEBZ User Manual

Evaluation Board User Guide

EVALUATION BOARD CONFIGURATION

SETTING UP THE EVALUATION BOARD

In order to allow evaluation of any one of over 40 RS-485
transceivers, the evaluation boards are supplied with an
unpopulated footprint for the RS-485 transceiver. The
evaluation board allows all of the input and output functions
to be exercised without the need for additional external
components. Jumper configurations are shown in Table 2.
To use the EVAL-RS485HDEBZ, fit an 8-lead SOIC half-duplex
transceiver to the footprint in the center of the board. For the
EVAL-RS485FD8EBZ, fit an 8-lead SOIC full-duplex trans-
ceiver to the footprint, and for the EVAL-RS485FDEBZ, a
14-lead SOIC full-duplex transceiver. Refer to Table 1 for a list
of parts available for each board.
The board is powered by connecting a 3.3 V or 5 V power
supply (refer to Table 1) to the screw terminals for VCC and
GND at the top of the evaluation board. A 22 µF or 10 µF
decoupling capacitor, C1, is fitted at the connector between
VCC and GND. The VCC pin of the RS-485 transceiver is fitted
with a decoupling capacitor of 100 nF, with a second footprint
for an optional additional capacitor.
Correspondingly labeled test points allow monitoring of the
power supply to the board and probe reference to ground.
Table 1. RS-485 Device and Board Cross Reference
Power Supply
Enhanced ESD, 3.3 V Supply
Enhanced ESD, 5 V Supply
Standard, 3.3 V Supply
Standard, 5 V Supply
Half-Duplex, 8-Lead
EVAL-RS485HDEBZ
ADM3072E
ADM3075E
ADM3078E
ADM3483E
ADM3485E
ADM3486E
ADM483E
ADM485E
ADM487E
ADM1487E
ADM3483
ADM3485
ADM3493
ADM1485
ADM1486
ADM4850
ADM4851
ADM4852
ADM4853
ADM483
ADM485
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INPUT/OUTPUT CONNECTIONS

Digital I/O is connected via a screw terminal block on the left
of the board, allowing wire connections to equipment or a
UART. All boards include connections for data input (DI) and
receiver output (RO). The half-duplex and 14-lead SOIC full-
duplex evaluation boards also have connections for receiver
enable ( RE ) and driver enable (DE). Alternatively, these inputs
can be driven by jumper connections to VCC and GND and/or
connected together (see Table 2).
Connections to an RS-485 bus are made via a screw terminal
block on the right of the board. For the half-duplex board, there
are two bus I/O signals, A and B, for noninverting and inverting
signals, respectively. For full-duplex boards, there are two input
bus signals, A and B, for noninverting and inverting signals,
respectively, and two corresponding output signals, Y and Z.
The bus cable may also include a common ground connection
or shield. These may also be connected to the screw terminal
block on the right of the board.
Test points are available on the board and appropriately labeled
for all digital and bus I/O signals.
Full-Duplex, 8-Lead
EVAL-RS485FD8EBZ
ADM3071E
ADM3074E
ADM3077E
ADM3488E
ADM3490E
ADM1490E
ADM3488
ADM3490
ADM488
ADM488A
ADM4854
ADM4855
ADM4856
ADM4857
UG-543
Full-Duplex, 14-Lead
EVAL-RS485FDEBZ
ADM3070E
ADM3073E
ADM3076E
ADM3491E
ADM1491E
ADM3491
ADM489
ADM489A