Cirrus Logic CDB5532U User Manual
CDB5532U
CDB5532U Evaluation Board and Software
Features
USB Communication with PC
On-board Microcontroller
On-board Voltage Reference
Evaluation Software
– Register Setup & Chip Control
– FFT Analysis
– Time Domain Analysis
– Noise Histogram Analysis
Interface Header for External Microcontroller
CRYSTAL
4.9152 MHz
CS5532
AIN1+
AIN1-
AIN2+
AIN2-
AIN1+
AIN1-
AIN2+
AIN2-
SDI
SDO
SCLK
CS
A0
A1
General Description
The CDB5532U is an inexpensive tool designed to evaluate the functionality and performance of the CS5532.
The CS5532 datasheet should be read and consulted
when using the CDB5532U evaluation board.
The evaluation board includes a C8051F320 microcontroller with a USB interface. The microcontroller controls
the serial communication between the evaluation board
and the PC via the firmware, enabling quick and easy access to all of the CS5532’s registers and functions.
The CDB5532U includes software for data capture, time
domain analysis, histogram analysis, and frequency domain analysis.
ORDERING INFORMATION
CDB5532U Evaluation Board
VA- VA+
Interface Header
GND
VD+
C8051F320
Microcontroller
+5 V
RESET
CIRCUITRY
USB
CONNECTOR
http://www.cirrus.com
VREF+
VREF-
VREF+
VREF-
Copyright © Cirrus Logic, Inc. 2007
(All Rights Reserved)
VREF
Source
Select
LT1019
AUG ‘07
DS807DB1
TABLE OF CONTENTS
1. HARDWARE ............................................................................................................................. 3
1.1 Introduction ........................................................................................................................ 3
1.2 Evaluation Board Overview ................................................................................................ 3
1.2.1 Analog Section ...................................................................................................... 3
1.2.2 Digital Section ....................................................................................................... 4
1.2.3 Power Supply Section ........................................................................................... 4
2. SOFTWARE .............................................................................................................................. 5
2.1 Installation Procedure ........................................................................................................ 5
2.1.1 CDB553xU GUI Software Installation Instructions ................................................ 5
2.1.2 Installing the USB Drivers ..................................................................................... 5
2.1.3 Running the GUI ................................................................................................... 5
2.2 Using the Software ............................................................................................................. 5
2.2.1 Start-Up Window ................................................................................................... 6
2.2.2 Setup Window ....................................................................................................... 7
2.2.3 Data Collection Window ...................................................................................... 10
2.2.4 Configuration Window ......................................................................................... 11
2.3 Collecting Data Sets ........................................................................................................ 12
2.4 Saving and Printing Data ................................................................................................. 12
2.5 Retrieving Saved Data From a File .................................................................................. 12
2.6 Analyzing Data ................................................................................................................. 12
2.7 Histogram Information ......................................................................................................13
2.8 Frequency Domain Information ........................................................................................ 13
2.9 Time Domain Information ................................................................................................. 13
3. SCHEMATICS ......................................................................................................................... 14
4. BOARD LAYOUT ................................................................................................................... 17
REVISION HISTORY ................................................................................................................. 22
CDB5532U
LIST OF FIGURES
Figure 1. CDB553xU Start-Up Screen ............................................................................................ 6
Figure 2. CDB5532U Setup Window............................................................................................... 7
Figure 3. CDB5532U Channel Setup Register Window .................................................................. 8
Figure 4. CDB5532U Calibration Window ....................................................................................... 9
Figure 5. CDB5532U Data Collection Window.............................................................................. 10
Figure 6. CDB5532U Configuration Window................................................................................. 11
Figure 7. Analog Section ............................................................................................................... 14
Figure 8. Digital Section ................................................................................................................ 15
Figure 9. Power Supply ................................................................................................................. 16
Figure 10. Top Silkscreen ............................................................................................................. 17
Figure 11. Top Routing.................................................................................................................. 18
Figure 12. Bottom Routing ............................................................................................................ 19
Figure 13. Bottom Silkscreen ........................................................................................................ 20
LIST OF TABLES
Table 1. Voltage Reference Selection for VREF+ .......................................................................... 4
Table 2. Voltage Reference Selection for VREF- ........................................................................... 4
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CDB5532U
1. HARDWARE
1.1 Introduction
The CDB5532U evaluation board provides a quick means of evaluating the CS5532 Analog-to-Digital
Converter (ADC). The CS5532 is a highly integrated ∆Σ ADC which uses charge-balance techniques to
achieve 24-bit performance. The CS5532 includes a very-low-noise, chopper-stabilized instrumentation
amplifier (6 nV/sqrt(Hz) @ 0.1 Hz) with selectable gains of 1x, 2x, 4x, 8x, 16x, 32x, and 64x. This ADC
also includes a fourth order ∆Σ modulator followed by a digital filter which provides twenty selectable output word rates of 6.25 Hz, 7.5 Hz, 12.5 Hz, 15 Hz, 25 Hz, 30 Hz, 50 Hz, 60 Hz, 100 Hz, 120 Hz, 200 Hz,
240 Hz, 400 Hz, 480 Hz, 800 Hz, 960 Hz, 1.6 kHz, 1.92 kHz, 3.2 kHz and 3.84 kHz (XIN = 4.9152 MHz).
The CDB5532U is shipped with a CS5532 device soldered at U2. However, the CS5531, CS5533, or
CS5534 can be soldered in this same location. The CDB553xU software supports all four devices.
1.2 Evaluation Board Overview
The CDB5532U evaluation board is partitioned into two main sections: analog and digital. The analog section consists of the CS5532 and a precision voltage reference. The digital section consists of the microcontroller, the reset circuitry, and the USB interface. The board also has power supply connections which
accommodate all of the various supply options of the CS5532.
The evaluation board’s analog section operates from either a single +5 V, dual ±2.5 V, or dual ±3 V power
supply. The evaluation board interfaces the CS5532 to an IBM
accomplish this, the board comes equipped with a microcontroller and a USB cable which physically interfaces the evaluation board to the PC. The software provides easy access to the internal registers of the
CS5532, and provides a means to display and evaluate the performance of the ADC in the time domain
or the frequency domain.
®
compatible PC with a USB interface. To
1.2.1 Analog Section
The CS5532 is a high-precision ∆Σ ADC designed to accurately measure one or two fully-differential analog voltage inputs while operating from a 4.9152 MHz crystal.
The evaluation board provides separate screw terminals to connect signals to each of the two input channels. The input screw terminals are labeled as AIN1 & AIN2, which correspond to physical input channels
1 & 2, respectively. A simple RC network on each channel filters the sensor’s output to reduce any interference picked up by the input leads. The -3 dB corner of the filter is approximately 52 kHz differential and
56 kHz common mode. Figure 7 illustrates the schematic of the analog section.
The evaluation board provides three voltage reference options for VREF+ and VREF-. The three reference options for VREF+ include: VA+, the on-board LT1019 voltage reference, and external input (J12).
Table 1 illustrates the options available. With the J17 jumper in position VA+, the reference is supplied by
the VA+ analog supply. With the J17 jumper in position LT1019, the LT1019 provides a +2.5 V reference
(the LT1019 was chosen for its low drift, typically 5 ppm/°C). By setting the J17 jumper to position VREF+,
the user can supply an external voltage reference to J12’s VREF+ input.
The three reference options for VREF- include: VA-, GND, and external input (J12). Table 2 illustrates the
options available. With the J18 jumper in position VA-, the reference is supplied by the VA- analog supply.
With the J18 jumper in position GND, the VREF- pin is connected to the board ground. By setting the J18
jumper to position VREF-, the user can supply an external voltage reference to J12’s VREF- input.
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Table 1. Voltage Reference Selection for VREF+
Reference Description J17
CDB5532U
VA+
LT1019
VREF+
Selects Positive
Analog Power
Supply
Selects on-Board
LT1019 Reference
(5ppm/
°C)
Selects External
Reference Source
(J12)
VA+
LT1019
REF+
VA+
LT1019
REF+
VA+
LT1019
REF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
O O VREF+
Table 2. Voltage Reference Selection for VREF-
Reference Description J18
VA-
GND
VREF-
Selects Negative
Analog Power
Supply
Selects Board
Gnd
Selects External
Reference Source
(J12)
VA GND
REF-
VA GND
REF-
VA GND
REF-
O O VREFO O VREFO O VREF-
O O VREFO O VREFO O VREF-
O O VREFO O VREFO O VREF-
1.2.2 Digital Section
Figure 8 illustrates the schematic of the digital section. It contains the microcontroller, USB interface, EEPROM, JTAG header, reset circuitry, and an external interface header. The microcontroller interfaces the
™
SPI
and MICROWIRE™ compatible serial port of the CS5532 with the USB connection to the PC. Note
that the SCLK and SDI signals are level shifted to support both +3.3 V and +5 V digital operation.
The microcontroller EEPROM is used to store firmware. An external interface header, J19, is provided to
allow the CDB5532U to be interfaced with an external microcontroller. To use this serial interface, the
0 ohm resistors R9, R10, R23, and R27 should be removed to disconnect the on-board microcontroller
from the serial interface.
1.2.3 Power Supply Section
Figure 9 illustrates the power supply connections to the evaluation board. VA+ supplies the positive analog supply for the CS5532 and the LT1019 reference. Header J14 allows the VA+ supply to be sourced
from either the VA+ binding post (J2), or from the +5 V binding post (J3). VA- supplies the negative analog
supply for the analog section. Header J13 allows the VA- supply to be sourced from either the VA- binding
post (J1), or connected to the board ground. Note that the VA- supply should be connected to ground
when powering the CDB5532U from a single +5 V analog supply. VD+ supplies the digital section of the
ADC and level shifters. Header J15 allows the VD+ supply to be sourced from the VD+ binding post (J5),
the +5 V binding post (J3), or the regulated +3.3 V supply derived from the microcontroller. The +5 V binding post supplies the microcontrollers internal regulator.
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CDB5532U
2. SOFTWARE
The evaluation board comes with software and a USB cable to link the evaluation board to the PC. The
software is designed to run under Windows
2.1 Installation Procedure
2.1.1 CDB553xU GUI Software Installation Instructions
1. Ensure the CDB5532U USB cable is disconnected from the PC.
®
2000 or later.
2. Open GUI software installation folder CDB553x_cvidistkit.Eval5534U
3. Run SETUP.EXE by double clicking on the filename.
4. Select Next, I Accept License Agreement, Next, Next, Finish.
2.1.2 Installing the USB Drivers
1. Apply power to the CDB5532U. Press and release the Reset switch, S1.
2. Use the included USB cable to connect the CDB5532U to the PC. The PC operating system should
automatically launch the Found New Hardware wizard.
3. From the installation wizard, select Install from a list or specific location (Advanced). Select Search
for the best driver in these locations.
4. Select Include this location in the search.
5. Click the Browse... button.
6. Go to folder C:/Program Files/Eval5534U/Driver and click OK.
7. Press the Next button.
8. A Hardware Installation dialog will appear. Press Continue Anyway.
9. Select Browse... and go to folder C:/Program Files/Eval5534U/Driver. Press Open.
10. A Files Needed dialog will appear. Press OK.
11. The Found New Hardware wizard will appear. Press the Finish button.
Ö
Volume1.
2.1.3 Running the GUI
Run the program by selecting StartÖAll ProgramsÖEval5534UÖEval5534_U.
2.2 Using the Software
Before launching the evaluation program, the user should set up the CDB5532U evaluation board, select
the proper jumper settings as described in Section 1, ensure the board is connected to an open USB port
on the PC, and apply power to the board.
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CDB5532U
2.2.1 Start-Up Window
When the evaluation program is launched, the start-up window will appear. This window contains information concerning the software’s title, revision number, copyright date, etc.
Figure 1. CDB553xU Start-Up Screen
At the top of the screen is a menu bar which displays user options. The menu bar item Window is initially
disabled to prevent conflicts with other serial communications devices. After selecting the data source in
the Options menu, the Window menu item will become available.
2.2.1.1 Options
The Options menu item allows the user to select the source of the data and to configure the appearance
of the graphs. The user has two options for the data source: USB and File. If USB is selected, the evaluation software will be ready to communicate with the CDB5532U via the USB connection. At this point,
the Part menu item is active and the appropriate CS553x device can be selected. If File is selected, the
evaluation software will prompt the user to select the appropriate data file. This option allows the user to
view previously captured data without having a CDB5532U connected to the PC. See section ‘Retrieving
Saved Data From a File” on page 12 for more details.
The Plot Options window can be accessed by pulling down the Options menu and clicking on Plot Options.
In this window, the user can change the background color, the plot line color, and the peak indicator color.
The Harmonic and Peak indicators can also be turned on or off in this window.
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CDB5532U
2.2.1.2 Window Menu
After the user selects the appropriate setup, the Window option becomes available in the Start-up window.
The Window pull-down has three options: Start-Up Window, Setup Window, and Data Collection Window.
2.2.2 Setup Window
The Setup window allows the user to access the internal registers of the CS5532. See Figure 5.
Figure 2. CDB5532U Setup Window
In the Setup window, all of the ADC’s registers are displayed as hexadecimal values. The configuration
register’s settings are also defined in this window.
Update Registers: The Update Registers button will read all the register values from the CS5532 and
update the hexadecimal values displayed on the screen. It is a good idea to press the Update Registers
button when entering the Setup window, or after modifying any registers to reflect the current status of the
part.
Reset Serial Port: When this button is selected, the software will send the synchronization sequence dis-
cussed in the CS5532 datasheet to the ADC. This sequence brings the CS5532’s serial port back to the
command mode, but does not reset any of the registers in the part.
Reset Part: When this button is selected, a ‘1’ is written to the RS bit in the configuration register to reset
the part. After a reset, the registers will all return to their default values as discussed in the CS5532
datasheet.
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