Cirrus Logic CDB5534U User Manual

CDB5534U

CDB5534U Evaluation Board and Software

Features

z USB Communication with PC z On-board Microcontroller z On-board Voltage Reference z Evaluation Software

– Register Setup & Chip Control – FFT Analysis – Time Domain Analysis – Noise Histogram Analysis

z Interface Header for External Microcontroller

CRYSTAL

4.9152 MHz

CS5534

AIN1+

AIN1-

AIN2+

AIN2-

AIN3+

AIN1+

AIN1-

AIN2+

AIN2-

AIN3+

SDI

SDO

SCLK

A0 A1

General Description

The CDB5534U is an inexpensive tool designed to evaluate the functionality and performance of the CS5534. The CS5534 datasheet should be read and consulted when using the CDB5534U 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 CS5534’s registers and functions.

The CDB5534U includes software for Data Capture, Time Domain Analysis, Histogram Analysis, and Frequency Domain Analysis.

ORDERING INFORMATION

CDB5534U Evaluation Board

VA- VA+

Interface Header

GND

VD+

C8051F320

Microcontroller

+5 V

RESET

CIRCUITRY

USB

CONNECTOR

AIN4+

VREF+

VREF-

http://www.cirrus.com

AIN3-

AIN4-

AIN3-

VREF+

AIN4+

VREF-

AIN4-

VREF

Source

Select

LT1019

NOV ‘06

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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 .............................................................................................................................. 9

2.1 Installation Procedure ...................................................................... .... ... ... ... .... .................9

2.1.1 CDB5530U GUI Software Installation Instructions ..... ........................................... 9

2.1.2 Installing the USB Drivers .....................................................................................9

2.1.3 Running the GUI ...................................................................................................9

2.2 Using the Software ................................. .... ... ..................................................................... 9

2.2.1 Start-Up Window ................................................. .... ... ... ...................................... 10

2.2.2 Setup Window .....................................................................................................11

2.2.3 Data Collection Window ......................................................................................14

2.2.4 Configuration Window ................................................ ... ... ................................... 15

2.3 Collecting Data Sets ........................................................................................................16

2.4 Saving and Printing Data .................................................................................................16

2.5 Retrieving Saved Data From a File ..................................................................................16

2.6 Analyzing Data ....... .......................................... ... .... .......................................... ... ............16

2.7 Histogram Information ......................................................................................................17

2.8 Frequency Domain Information ..................... ... ... .... ...................................... .... ... ... ... ......17

2.9 Time Domain Information ................................................................................................. 17

3. BOARD LAYOUT ................................................................................................................... 18

CDB5534U

LIST OF FIGURES

Figure 1. Analog Section................................................................................................................. 6

Figure 2. Digital Section .................................................................................................................. 7

Figure 3. Power Supply................................................................................................................... 8

Figure 4. CDB5534U Start-Up Screen ..........................................................................................10

Figure 5. CDB5534U Setup Window............................................................................................. 11

Figure 6. CDB5534U Channel Setup Register Window................................................................ 12

Figure 7. CDB5534U Calibration Window.....................................................................................13

Figure 8. CDB5534U Data Collection Window..............................................................................14

Figure 9. CDB5534U Configuration Window.................................................................................15

Figure 10. Top Silkscreen .............................................................................................................18

Figure 11. Top Side Layout...........................................................................................................19

Figure 12. Bottom Silkscreen........................................................................................................20

Figure 13. Bottom Side Layout...................................................................................................... 21

LIST OF TABLES

Table 1. Voltage Reference Selection for VREF+ ..........................................................................4

Table 2. Voltage Reference Selection for VREF- ...........................................................................4

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CDB5534U

1. HARDWARE

1.1 Introduction

The CDB5534U evaluation board provides a quick means of evaluating the CS5534 Analog-to-Digital Converter (ADC). The CS5534 is a highly integrated ∆Σ ADC which uses charge-balance techniques to achieve 24-bit performance. The CS5534 includes a very low noise chopper-stabilized instrumentation amplifier (6 nV/sqrt(Hz) @ 0.1 Hz) with selectable gains of 1×, 2×, 4×, 8×, 16×, 32×, and 64×. 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 CDB5534U is shipped with a CS5534 device soldered at U2. However, the CS5531, CS5532, or CS5533 can be soldered in this same location. The CDB5534U software supports all four devices.

1.2 Evaluation Board Overview

The CDB5534U evaluation board is partitioned into two main sections: analog and digital. The analog section consists of the CS5534 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 CS5534.

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 CS5534 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 CS5534, 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 CS5534 is a high precision ∆Σ converter designed to accurately measure up to four 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 four input channels. The input screw terminals are labeled as AIN1 through AIN4, which correspond to physical input channels 1 through 4 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 ap proximately 52 kHz differential and 56 kHz common mode. Figure 1 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 LT10 19, the LT 1019 provides a +2.5 V reference (the LT1019 was chosen for its low drift, typically 5ppm/°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

CDB5534U

VA+

LT1019

VREF+

Selects Positive

Analog Power

Supply

Selects on-Board

LT1019 Reference

(5ppm/

°C)

Selects External

Reference Source

(J12)

VA+ LT1019 REF+

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-

O O VREFO O VREFO O VREF-

1.2.2 Digital Section

Figure 2 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 CS5534 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 CDB5534U 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 3 illustrates the power supply connections to the evaluation board. VA+ supplies the positive analog supply for the CS5534 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 CDB5534U 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),

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CDB5534U

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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CDB5534U

Figure 1. Analog Section

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CDB5534U

Figure 2. Digital Section

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