Cirrus Logic CS5550 User Manual
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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/CVITM 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 evaluating the functionality and performance of the CS5550 A/D
converter. The CS5550 datasheet is supplied in conjunction with the CDB5550 evaluation board.
The evaluation board includes a C8051F320 microcontroller, a USB interface, drivers, and firmware. 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 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
AIN1+
AIN1+
AIN1-
AIN1-
AIN2+
AIN2+
AIN2-
AIN2-
Ext
Ref
Ext
Gnd
Ref
Gnd
Cirrus Logic, Inc.
http://www.cirrus.com
Sele ctable
Selectable
Divider
Divider
CRYSTAL
4.096 MHz
4.096 MHz
CS5550
AIN1+
AIN1+
AIN1-
AIN1-
AIN2+
AIN2+
AIN2-
AIN2-
OUT
CRYSTAL
CS5550
CS
SDI
SDO
SDO
SCLK
SCLK
RESET
INT
RESET
VREF
OUT
VREF
IN
Interface Header
Interface Header
CS
SDI
INT
IN
Copyright © Cirrus Logic, Inc. 2004
(All Rights Reserved)
+5 V
+5 V
GND
GND
C8051F320
C8051F320
Microcontroller
Microcontroller
RESET
CIRCUITRY
CONNECTOR
USB
CONNECTOR
RESET
CIRCUITRY
USB
JUN ‘04
DS630DB1
1
TABLE OF CONTENTS
1. HARDWARE ............................................................................................................................. 4
1.1 Introduction ........................................................................................................................ 4
1.2 Evaluation Board Overview ................................................................................................ 4
1.2.1 Analog Section ...................................................................................................... 4
1.2.2 Digital Section .......................................................................................................5
1.3 Power Supply ..................................................................................................................... 6
2. SOFTWARE .............................................................................................................................. 6
2.1 Installation Procedure ........................................................................................................6
2.2 Using the Software ............................................................................................................. 6
2.2.1 Start-Up Window ................................................................................................... 6
2.2.2 Setup Window ....................................................................................................... 8
2.2.3 Calibration Window ............................................................................................... 9
2.2.4 Conversion Window .............................................................................................. 9
2.2.5 Data Collection Window ...................................................................................... 11
2.3 Retrieving Saved Data From a File .................................................................................. 13
2.4 Analyzing Data ................................................................................................................. 13
2.5 Histogram Information ......................................................................................................14
2.5.1 MEAN ............................................................................................................................14
2.5.2 STD_DEV .....................................................................................................................15
2.5.3 VARIANCE ....................................................................................................................15
2.5.4 MAXIMUM .....................................................................................................................15
2.5.5 MINIMUM ......................................................................................................................15
2.5.6 BIN .................................................................................................................................15
2.5.7 MAGNITUDE ................................................................................................................15
2.6 Frequency Domain Information ........................................................................................ 16
2.6.1 S/PN ..............................................................................................................................16
2.6.2 SINAD ...........................................................................................................................16
2.6.3 S/D .................................................................................................................................16
2.6.4 SNR ...............................................................................................................................16
2.6.5 FREQUENCY ...............................................................................................................16
2.6.6 MAGNITUDE ................................................................................................................16
2.6.7 # of AVG ........................................................................................................................16
2.7 Time Domain Information ................................................................................................. 17
2.7.1 MAXIMUM .....................................................................................................................17
2.7.2 MINIMUM ......................................................................................................................17
2.7.3 COUNT .........................................................................................................................17
2.7.4 MAGNITUDE ................................................................................................................17
3. REVISIONS ............................................................................................................................. 23
CDB5550
2
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 ................................................................................................. 8
Figure 5. CDB5550 Calibration Window ......................................................................................... 9
Figure 6. CDB5550 Conversion Window ...................................................................................... 10
Figure 8. CDB5550 Configuration Window ................................................................................... 12
Figure 9. CDB5550 Histogram Plot............................................................................................... 14
Figure 10. CDB5550 Frequency Domain Plot ............................................................................... 16
Figure 11. CDB5550 Time Domain Plot........................................................................................ 17
Figure 12. Digital Section and Power Supply................................................................................ 18
Figure 13. Analog Section............................................................................................................. 19
Figure 14. Silkscreen .................................................................................................................... 20
Figure 15. Top Side....................................................................................................................... 21
Figure 16. Bottom Side ................................................................................................................. 22
LIST OF TABLES
Table 1. Analog Input Selection ...................................................................................................... 4
Table 2. VREFIN Source Selection................................................................................................. 5
Table 3. External Voltage Divider Selection.................................................................................... 5
Table 4. Revisions......................................................................................................................... 23
CDB5550
3
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. Additionally, analysis software provides easy access to the internal
registers of the CS5550, and provides a means to display the performance in the time domain or frequency domain.
1.2 Evaluation Board Overview
The board is partitioned into two main sections: analog and digital. The analog section consists of the
CS5550, analog inputs, and an optional external voltage reference input. The digital section consists of
the microcontroller, interface header, reset circuitry, and the USB interface. The board also provides two
binding posts for easy power supply connectivity.
1.2.1 Analog Section
The CDB5550 provides several options for driving the analog inputs into the converter. These options include an external analog source, the voltage reference, and ground. Refer to Table 1.
Reference Description J11 Reference Description J5
AIN1+
VREF
GND
Selects the external
analog input (J13)
Selects the voltage ref-
erence sourced from
J7
Selects the ground
reference
O O AIN1+
O O VREF
O O GND
O O AIN1+
O O VREF
O O GND
O O AIN1+
O O VREF
O O GND
AIN2+
VREF
GND
Selects the external
analog input (J10)
Selects the voltage ref-
erence sourced from
J7
Selects the ground
reference
O O AIN2+
O O VREF
O O GND
O O AIN2+
O O VREF
O O GND
O O AIN2+
O O VREF
O O GND
Reference Description J14 Reference Description J9
AIN1-
VREF
GND
Selects the external
analog input (J13)
Selects the voltage ref-
erence sourced from
J7
Selects the ground
reference
O O AIN1O O VREF
O O GND
O O AIN1O O VREF
O O GND
O O AIN1O O VREF
O O GND
AIN2-
VREF
GND
Selects the external
analog input (J10)
Selects the voltage ref-
erence sourced from
J7
Selects the ground
reference
O O AIN2O O VREF
O O GND
O O AIN2O O VREF
O O GND
O O AIN2O O VREF
O O GND
Table 1. Analog Input Selection
The external analog inputs also provide +5 V and ground connectors which can be used to power a load
cell.
4
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
CS5550 VREFOUT
Selects the external voltage reference
(J4)
Selects the internal voltage reference
from the CS5550
Table 2. VREFIN Source Selection
O O VREFOUT
O O Ext VREF
O O VREFOUT
O O Ext VREF
A selectable voltage divider for the external reference is also provided. The external voltage applied to the
terminal block J4 can be divided by a factor of 1, 2, 4, or 8. The voltage divider is controlled by header J1.
Refer to Table 3.
Reference Description J7
O O /1
O O /2
O O /4
O O /8
O O /1
O O /2
O O /4
O O /8
O O /1
O O /2
O O /4
O O /8
/1
/2
/4
Divides the external voltage applied to J4
by a factor of 1
Divides the external voltage applied to J4
by a factor of 2
Divides the external voltage applied to J4
by a factor of 4
O O /1
O O /2
O O /4
O O /8
/8
Divides the external voltage applied to J4
by a factor of 8
Table 3. External Voltage Divider Selection
1.2.2 Digital Section
The digital section of the CDB5550 consists of the microcontroller, interface header, reset circuitry, and
the USB interface. The microcontroller handles the communication between the PC and the CS5550. This
device is pre-programmed and requires no additional code in order to operate.
An SPI interface header is provided via J8 for use with an external microcontroller. However, if an external
microcontroller is used, the on-board microcontroller (U3) must be disconnected from the SPI port. This
can be accomplished by removing the 0 ohm resistors R11, R12, R13, R15, R17, and R18.
The CDB5550 has a pushbutton reset switch, S1. This reset button will reset the microcontroller which
will then reset the CS5550, resetting all registers to their default values.
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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. However, the CDB5550 can
easily be modified to run the digital supply of the CS5550 at +5 V by removing R8 and populating R9 with
a 0 ohm resistor.
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 98TM or later. After installing the software, read the readme.txt
file for any last minute updates or changes.
2.1 Installation Procedure
The CDB5550 comes with an auto-booting CD that contains the required software to interface to the evaluation board. To install the software, place the CD into the CDROM drive and follow the on-screen instructions. The user will be prompted to select the destination for the installed program.
2.2 Using the Software
Before launching the software, the user should set up the CDB5550 evaluation board, select the proper
jumper settings as described in Section 1, and connect the board to an open USB port on the PC using
the provided cable. Once the board is powered on, the user can start the software program.
2.2.1 Start-Up Window
When the software is launched, the Start-Up window will appear. This window contains information concerning the software’s title, revision number, copyright date, etc. See Figure 1.
Figure 1. CDB5550 Start-Up Screen
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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. If the Data from Disk setup 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 CDB5550 connected to the PC. See Section 2.3 for more details.
After the user selects the appropriate setup, the Menu option becomes available in the Start-Up window.
The Menu pull-down has five options: Start-Up Window, Setup Window, Calibration Window, Conversion
Window, and Data Collection Window. See Figure 3.
Figure 3. CDB5550 Menu Options
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