DEM-ADS1216
SBAU038
2
INITIAL CONFIGURATION
The DEM-ADS1216 is designed to be operational without any
user configuration except connecting the power supplies and the
communications cable to the PC printer port. To use the internal
reference voltage, jumpers T1 and T2 should be installed.
POWER SUPPLY
The analog and digital supplies should be connected to-
gether at the power supply. That means that a pair of wires
should go from V
CC
and AGND to the power supply and a
separate pair of wires should go from V
DD
and DGND to the
same +5Vpower supply.
VOLTAGE REFERENCE
With jumpers T1 and T2 installed the DEM-ADS1216 Demo
Board will use the internal reference. These jumpers can be
replaced and connections made to the pins, to use an external
reference.
CLOCK
A 2.4576MHz crystal is connected to the XIN and XOUT
pins to provide a convienient frequency for 60Hz rejection.
PC BOARD LAYOUT
The DEM-ADS1216 demo board consists of a 2-layer PC
board. To achieve the highest level of performance, surface-
mount components are used wherever possible. This reduces
the trace length and minimizes the effects of parasitic capaci-
tance and inductance. The demo board has a divided ground
with all the analog signals over one portion and the digital
signals in the other. Keep in mind that this approach may not
necessarily yield optimum performance results when design-
ing the ADS1216 into different individual applications. In any
case, thoroughly bypassing the power supply and reference
pins of the converter is strongly recommended.
The breadboard area is provided so that input filters can be
added. As shipped, the board includes an R-C filter (49.9
and 47pF) on each input with 0.1
μ
F differential capacitor
between adjacent channels.
WINDOWS SOFTWARE
The ADS1216 uses registers and a 1-byte opcode to control
the operation. The evaluation software provides a conve-
nient method to issue the commands and receive the results.
It also can display the results of acquired data, as shown in
Figure 1, and perform a frequency analysis, as shown in
Figure 2.
The program is organized with pull-down menus as follows:
File
Display Data List
Save Data
Save FFT Data
Print Data
Exit
Configuration
Configure Digital Filter
Select Input Channel
Set IDACs/PGA/V
REF
Tests
Opcode Test
RAM R/W Test
Noise Test
Options
Data List Format
Voltage
Raw Hex
Raw Decimal
Set FFT Window
Rectangular
Hamming
Blackman
Blackman Harris
Continuous 5
th
Derivative
FFT Harmonic Bins
Number of Harmonic Bins
Number of DC Bins
Help
About ADS1216 Demo SW
FIGURE 1. Time Plot.
FIGURE 2. FFT Frequency Plot.