Digilent AIO1 - Manual

D D i i g g i i l l e e n n t t A A I I O O 1 1 M M a a n n u u a a l l
w w w . d i g i l e n t i n c . c o m ™
Revision: December 6, 2004 246 East Main | Pullman, WA 99163
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Copyright Digilent, Inc. All rights reserved 2 pages Doc: 502-035
Functional Description
The AIO1 board is a peripheral board designed to work with Digilent’s family of system boards. The
AIO1 contains analog-to-digital and digital-to-analog converters from Analog Devices, two dual op-
amps, a variety of analog signal I/O connectors, and a solderless breadboard. All analog components
use an on-board 5VDC voltage source. All unused I/O signals are passed through the AIO1 board so
that it can be used between a system board and other peripheral boards.
The solderless breadboard and op-
amps on the AIO1 can be used to
construct filters and amplifiers for the
data converters. Gain and frequency-
limiting resistor/capacitor networks can
be constructed on the breadboard,
and connected to the op-amps and
data converters using jumper wires
inserted into the breadboard
connector. The breadboard connector
can also be used to route analog I/O
signals to any one of eight connectors
included on the board (including BNC,
RCA, and 1/8 audio jacks).
The AIO1 uses an 8-bit, 200Ks
analog-to-digital converter (the
AD7823), and an 8-bit, 1Mhz digital-to-
analog converter (the AD7303), both
from Analog Devices. The AD8534 op-
amps (also from Analog Devices) can
drive 250mA outputs rail-to-rail with a
3Mhz bandwidth, so many useful
devices can be driven directly.
The IO1 board uses only twelve signals, all from the J2 connector. Of these, six are provided as
uncommitted digital I/Os (three inputs and three outputs), and six are used by the data converters.
Both data converters use a serial protocol with data signal, clock, and synchronizing signals. Only one
signal is returned to the system board, and it uses a 3.3V buffer so that lower-voltage system boards
can be used.
The J2 connector pin definitions are shown below (all J2 signals not shown pass through to J4).
The AOI1 has two voltage selections available. It can be operated with VCC 3.3V (for the Digilent
Pegasus Board) or 5Vv for all other Digilent System Boards. To use either voltage selection, place a
jumper on JP2 as outlined by the silkscreen on the AIO1.
Connector J2
A2D
Converter
(AD 7823)
D2A
Converter
(AD 7303)
74CH125
buffer
Solderless
Breadboard
Breadboard connector
Various I/O
connectors
V
IN
V
OUT
6 5
Serial
data
Op amps
All nodes
Data and control
Digital I/O
J1 signals pass through to J3;
unused J2 signals pass through to J4
Connector J1
Connector J3
Figure 1: AIO1 block Diagram