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Cirrus Logic, Inc.

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AIN1+

AIN1-

AIN2+

AIN2-

CRYSTAL

4.096 MHz

Ext

Ref

Gnd

GND

CS5550

RESET

INT

SCLK

SDO

SDI

C8051F320

Microcontroller

RESET

CIRCUITRY

USB

CONNECTOR

OUT

+5 V

VREF

Selectable

Divider

Interface Header

AIN1+

AIN1-

AIN2+

AIN2-

AIN1+

AIN1-

AIN2+

AIN2-

CRYSTAL

4.096 MHz

Ext

Ref

Gnd

GND

CS5550

RESET

INT

SCLK

SDO

SDI

C8051F320

Microcontroller

RESET

CIRCUITRY

USB

CONNECTOR

OUT

+5 V

VREF

Selectable

Divider

Interface Header

AIN1+

AIN1-

AIN2+

AIN2-

CDB5550

CDB5550 Evaluation Board and Software

Features

USB Communication with PC

On-board Microcontroller

Multiple Voltage Reference Options

- On-chip Reference

- External Reference with On-Board Precision

Dividers

LabWindows/CVI

Evaluation Software

- Register Setup & Chip Control

- FFT Analysis

- Time Domain Analysis

- Noise Histogram Analysis

Interface Header for External Microcontroller

Supports 3.3 V and 5.0 V Digital Operation of

the CS5550

General Description

The CDB5550 is an excellent means for quickly evaluat-

ing the functionality and performance of the CS5550 A/D

converter. The CS5550 datasheet is supplied in con-

junction with the CDB5550 evaluation board.

The evaluation board includes a C8051F320 microcon-

troller, a USB interface, drivers, and firmware. The

microcontroller controls the serial communication be-

tween the evaluation board and the PC via the firmware,

enabling quick and easy access to all of the CS5550’s

registers and functions.

The CDB5550 includes software for Data Capture, Time

Domain Analysis, Histogram Analysis, and Frequency

Domain Analysis.

ORDERING INFORMATION

CDB5550 Evaluation Board

JUN ‘04

DS630DB1

Summary of content (23 pages)

PAGE 1
\ CDB5550 CDB5550 Evaluation Board and Software Features General Description USB Communication with PC On-board Microcontroller Multiple Voltage Reference Options The CDB5550 is an excellent means for quickly evaluating the functionality and performance of the CS5550 A/D converter. The CS5550 datasheet is supplied in conjunction with the CDB5550 evaluation board.
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CDB5550 TABLE OF CONTENTS 1. HARDWARE ............................................................................................................................. 4 1.1 Introduction ........................................................................................................................ 4 1.2 Evaluation Board Overview ................................................................................................ 4 1.2.1 Analog Section ........................................................
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CDB5550 LIST OF FIGURES Figure 1. CDB5550 Start-Up Screen............................................................................................... 6 Figure 2. CDB5550 Setup Options.................................................................................................. 7 Figure 3. CDB5550 Menu Options .................................................................................................. 7 Figure 4. CDB5550 Setup Window ..............................................................
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CDB5550 1. HARDWARE 1.1 Introduction The CDB5550 evaluation board provides a quick means of evaluating the CS5550 A/D converter. The CDB5550 evaluation board’s analog section operates from a single +5 V power supply. The evaluation board interfaces the CS5550 to an IBMTM compatible PC via a USB interface. To accomplish this, the board comes equipped with a C8051F320 microcontroller and a USB connector which physically interfaces the evaluation board to the PC.
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CDB5550 The CDB5550 also provides options for sourcing the voltage reference for the CS5550. These options include the on-chip reference (VREFOUT), or an external reference. The voltage reference selection is controlled via the header J7. Refer to Table 2. Reference Description J7 Ext VREF Selects the external voltage reference (J4) O O O VREFOUT O Ext VREF CS5550 VREFOUT Selects the internal voltage reference from the CS5550 O O O VREFOUT O Ext VREF Table 2.
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CDB5550 1.3 Power Supply Power is supplied to the CDB5550 via two binding posts, +5 V (J2) and GND (J3). The +5 V supply powers the analog core of the CS5550 and the internal regulator of the microcontroller. The microcontroller regulator outputs a +3.3 V supply which is used to power the microcontroller as well as various other logic blocks. The digital core of the CS5550 is powered from the regulated +3.3 V supply.
PAGE 7
CDB5550 A pop-up window will also appear prompting the user to select the appropriate data source from the Setup menu, located in the upper left hand corner of the Start-Up window. The user has two options: USB and Data from Disk. See Figure 2. Figure 2. CDB5550 Setup Options If the USB setup is selected, the evaluation software will be ready to communicate with the CDB5550 via the USB connection.
PAGE 8
CDB5550 2.2.2 Setup Window The Setup Window allows the user to access the internal registers of the CS5550. From this window the user can click the View Register Values button to see the current values loaded in the Configuration, Mask, Status, and Cycle Count Registers. The Status Register will default to 1h because the invalid command bit is active low. See Figure 4. Figure 4. CDB5550 Setup Window 2.2.2.1.
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CDB5550 2.2.3 Calibration Window The Calibration Window allows the user to perform Offset and Gain calibrations on both channels. To perform an Offset calibration, connect the analog input to the referenced zero point (typically ground) and click on the calibration (cal) button for that given channel. The resulting calibration value will be displayed in both hexadecimal and decimal form below the button for that channel.
PAGE 10
CDB5550 will result in the data being updated ten times a second. Please note that the software only supports cycle counts between 400 to 4000 when in the Conversion Window. Figure 6. CDB5550 Conversion Window 2.2.4.1. Single Conversion Button On pressing this button, a single conversion will be performed. After the conversion is complete, the Result data column will update with the values present in each data register. 2.2.4.2.
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CDB5550 2.2.5 Data Collection Window The Data Collection Window allows the user to collect sample sets of data from the CS5550 and analyze them using time domain, FFT, and histogram plots. The user can then output this data to a file or make a hardcopy of the display. Figure 7. CDB5550 Data Collection Window 2.2.5.1. Time Domain / FFT / Histogram Selector This menu selects the type of data processing to perform on the collected data and display in the plot area.
PAGE 12
CDB5550 2.2.5.2. Config Button This button will bring up the configuration window, in which the user can modify the data collection specifications. Refer to Figure 8. Figure 8. CDB5550 Configuration Window Number of Samples This box allows the user to select the number of samples to collect, between 16 and 4096. Average When doing FFT processing, this box will determine the number of FFTs to average. FFTs will be collected and averaged when the Collect button is pressed.
PAGE 13
CDB5550 Note: When saving data, only the data channel being displayed on the plot will be saved to a file. 2.2.5.5. Zoom Button This button allows the user to zoom in on the plot by selecting two points in the plot area. Press the Restore button to return to the normal data plot, or press the Zoom button again to zoom in even further. 2.3 Retrieving Saved Data From a File The CDB5550 software allows the user to save data to a file, and retrieve it later when needed.
PAGE 14
CDB5550 2.5 Histogram Information The following is a description of the indicators associated with Histogram Analysis. Histograms can be plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector to Histogram. Figure 9 shows a typical histogram plot. Figure 9. CDB5550 Histogram Plot 2.5.1 MEAN Indicator for the mean of the data sample set.
PAGE 15
CDB5550 2.5.2 STD_DEV Indicator for the Standard Deviation of the collected data set. The Standard Deviation is calculated using the following formula n-1 StDev = Σ (X i - M ean) 2 i=0 n 2.5.3 VARIANCE Indicates the Variance for the current data set. The variance is calculated using the following formula: n-1 Var = Σ (X i - Mean) 2 i=0 n 2.5.4 MAXIMUM Indicator for the maximum value of the collected data set. 2.5.5 MINIMUM Indicator for the minimum value of the collected data set. 2.5.
PAGE 16
CDB5550 2.6 Frequency Domain Information The following describes the indicators associated with FFT (Fast Fourier Transform) Analysis. FFT data can be plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector to FFT. Figure 10 illustrates a typical Frequency Domain plot. Figure 10. CDB5550 Frequency Domain Plot 2.6.1 S/PN Indicator for the Signal-to-Peak Noise Ratio (decibels). 2.6.2 SINAD Indicator for the Signal-to-Noise + Distortion Ratio (decibels). 2.6.
PAGE 17
CDB5550 2.7 Time Domain Information The following controls and indicators are associated with Time Domain Analysis. Time domain data can be plotted in the Data Collection Window by setting the Time Domain / FFT / Histogram selector to Time Domain. Figure 11. CDB5550 Time Domain Plot 2.7.1 MAXIMUM Indicator for the maximum value of the collected data set. 2.7.2 MINIMUM Indicator for the minimum value of the collected data set. 2.7.
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Figure 12.
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Figure 13.
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Figure 14.
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Figure 15.
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Figure 16.
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CDB5550 3. REVISIONS Table 4. Revisions Revision Date 1 June 2004 Change Initial Release Contacting Cirrus Logic Support For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at: http://www.cirrus.com/corporate/contacts/sales.cfm IMPORTANT NOTICE C irrus Logic, Inc. and its subsidiaries ("C irrus") believ e that the inform ation c ontained in this docum ent is accurate and reliable.