Cirrus Logic CRD5378 Manual

Single-channel seismic reference design

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Single-Channel Seismic Reference Design
Features
Single-channel Seismic Acquisition Node
– CS3302A hydrophone amplifier
– CS5373A ∆Σ modulator + test DAC
– CS5378 digital filter + PLL
– Precision voltage reference
On-board Microcontroller
– SPI
interface to digital filter
– USB communication with PC
Board Design
– Compact board size: 5" x 1.25" x 0.5"
– Detachable acquisition and telemetry nodes
PC Evaluation Software
– Register setup & control
– FFT frequency analysis
– Time domain analysis
– Noise histogram analysis
Data Aquisition Board (Actual Size)
www.cirrus.com
General Description
The CRD5378 board is a compact reference design for
the Cirrus Logic single-channel seismic chip set. Data
sheets for the CS3302A, CS5373A, and CS5378 devic-
es should be consulted when using the CRD5378
reference design.
Pin headers connect an external differential sensor to
the analog inputs of the measurement channel. An on-
board test DAC creates precision differential analog sig-
nals for in-circuit performance testing without an external
signal source.
The reference design includes an 8051-type microcon-
troller with hardware SPI™ and USB serial interfaces.
The microcontroller communicates with the digital filter
via SPI and with the PC evaluation software via USB.
The PC evaluation software controls register and coeffi-
cient initialization and performs time domain, histogram,
and FFT frequency analysis on captured data.
The CRD5378 board features a special breakout con-
nector used to detach the acquisition and telemetry
sections for remote sensor applications.
ORDERING INFORMATION
Reference Design Panel (Actual Size)
Copyright © Cirrus Logic, Inc. 2008
(All Rights Reserved)
CRD5378
Control Board (Actual Size)
CRD5378
Reference Design
JAN '08
DS639RD2

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Summary of Contents for Cirrus Logic CRD5378

  • Page 1 CRD5378 Single-Channel Seismic Reference Design Features General Description The CRD5378 board is a compact reference design for Single-channel Seismic Acquisition Node the Cirrus Logic single-channel seismic chip set. Data – CS3302A hydrophone amplifier sheets for the CS3302A, CS5373A, and CS5378 devic- –...
  • Page 2 CRD5378 REVISION HISTORY Revision Date Changes JAN 2007 Initial release. JAN 2008 Upgrade from CS3302 to CS3302A-ISZ/G (U19). Change (R27,R28,R29,R30) from 0ohms to 680ohms. DS639RD2...
  • Page 3 ING ATTORNEYS' FEES AND COSTS, THAT MAY RESULT FROM OR ARISE IN CONNECTION WITH THESE USES. Cirrus Logic, Cirrus, and the Cirrus Logic logo designs are trademarks of Cirrus Logic, Inc. All other brand and product names in this document may be trademarks or service marks of their respective owners.
  • Page 4: Table Of Contents

    1.3.2 Seismic Evaluation Software Installation .............. 8 1.3.3 USBXpress® Driver Installation ................8 1.3.4 Launching the Seismic Evaluation Software ............9 1.4 Self-Testing CRD5378 ..................... 10 1.4.1 Noise Test ......................10 1.4.2 Distortion Test ..................... 11 2. HARDWARE DESCRIPTION ....................12 2.1 Block Diagram .........................
  • Page 5 4. BILL OF MATERIALS ......................48 5. LAYER PLOTS ........................49 6. SCHEMATICS ........................57 LIST OF FIGURES Figure 1. CRD5378 Block Diagram....................12 Figure 2. Differential Pair Routing ....................29 Figure 3. Quad Group Routing...................... 29 Figure 4. Bypass Capacitor Placement..................30 LIST OF TABLES Table 1.
  • Page 6: Initial Setup

    J26 pin 19 = +3.3 V J26 pin 20 = 0 V • Connect the USB cable between the CRD5378 USB connector and the PC USB port. • Proceed to the Software Setup section to install the evaluation software and USB driver.
  • Page 7: Default Jumper Settings

    CRD5378 1.2.1 Default Jumper Settings * indicates the default 0 Ω jumper installations for CRD5378. Amplifier CS3301A CS3302A R8 + R9 *R10 Table 1. Amplifier Pin 13 Jumper Setting Input Clock Resistor Digital Filter Clock Resistor EXTERNAL CLOCK 4.096 MHz Manchester R15 + R41 + R42 1.024 MHz...
  • Page 8: Software Setup

    To install the USBXpress driver (after installing the Seismic Evaluation Software): • Connect CRD5378 to the PC through an available USB port and apply power. The PC will detect CRD5378 as an unknown USB device.
  • Page 9: Launching The Seismic Evaluation Software

    “C:\Program Files\Cirrus Seismic Evaluation\Driver\”. The PC will recognize and install the USBXpress device driver. • After driver installation, cycle power to CRD5378. The PC will automatically detect it and add it as a USBXpress device in the Windows Hardware Device Manager.
  • Page 10: Self-Testing Crd5378

    Noise and distortion self-tests can be performed once hardware and software setup is complete. First, initialize the CRD5378 reference design: • Launch the evaluation software and apply power to CRD5378. • Click ‘OK’ on the About panel to get to the Setup panel.
  • Page 11: Distortion Test

    CRD5378 • Once the Setup panel is set, select Configure on the Digital Filter sub-panel. • After digital filter configuration is complete, click Capture on the Data Capture sub-panel. • Once the data record is collected, the Analysis panel is automatically displayed.
  • Page 12: Hardware Description

    CRD5378 2. HARDWARE DESCRIPTION Block Diagram Figure 1. CRD5378 Block Diagram Major blocks of the CRD5378 reference design include: • CS3302A Hydrophone Amplifier • CS5373A ∆Σ Modulator + Test DAC • CS5378 Digital Filter + PLL • Precision Voltage Reference •...
  • Page 13: Analog Hardware

    External signals connect to CRD5378 through a 3-pin header on the left side of the PCB. This header makes a connection to the differential INA amplifier inputs and to either a GND or GUARD signal for con- nection to the sensor cable shields, if present.
  • Page 14 CRD5378 2.2.1.4 Input Protection Sensor inputs must have circuitry to protect the analog electronics from voltage spikes. Geophone coils are susceptible to magnetic fields (especially from lightning) and hydrophones can produce large voltage spikes if located near an air gun source.
  • Page 15 CRD5378 defaults depending on the sensor to be used. Refer to the recommended operating bias con- ditions for the selected sensor, which are available from the sensor manufacturer.
  • Page 16: Differential Amplifiers

    2.2.2.1 MCLK Input vs. GUARD Output By default, CRD5378 uses the CS3302A hydrophone amplifier. The CS3302A amplifier is a very high in- put impedance device and achieves a 1/f noise performance typically buried below the low-frequency ocean noise. To minimize leakage from high impedance sensors connected to the CS3302A amplifier, pin 13 produces a GUARD signal output to actively drive a sensor cable shield with the common mode volt- age of the sensor signal.
  • Page 17: Delta-Sigma Modulator

    CS5373A modulator inputs to bandwidth limit analog signals into the modulator. Ω For the CRD5378, the CS3301A/02A amplifier outputs are connected to external 680 series resistors and a differential anti-alias RC filter is created by connecting 20 nF of high linearity differential capacitance (2x 10 nF C0G) between each half of the rough and fine signals.
  • Page 18: Delta-Sigma Test Dac

    2.2.5 Voltage Reference A voltage reference on CRD5378 creates a precision voltage from the regulated analog supplies for the modulator and test DAC VREF inputs. Because the voltage reference output is generated relative to the negative analog power supply, VREF+ is near GND potential for bipolar power supplies.
  • Page 19: Digital Hardware

    CRD5378 2.2.5.1 VREF_MOD The voltage reference output is provided to the CS5373A ∆Σ modulator and test DAC through a low-pass RC filter. By filtering the voltage reference to the device, high-frequency noise is eliminated and any sig- nal-dependent sampling of VREF is isolated. The voltage reference signal is routed as a separate differ- ential pair from the large RC filter capacitor to control the sensitive VREF source-return currents and keep them out of the ground plane.
  • Page 20 2.3.1.2 Configuration - SPI Port On CRD5378, configuration of the digital filter is through the SPI port by the on-board 8051 microcontrol- ler, which receives commands from the PC evaluation software via the USB interface. Evaluation software commands can write/read digital filter registers, specify digital filter coefficients and start/stop digital filter operation.
  • Page 21 Loop Filter Architecture Internal If no external system clock is supplied to CRD5378, the CRD5378 can select a PLL input clock from a local oscillator. Using a clock divider, the on-board oscillator produces 1.024 MHz, 2.048 MHz, 4.096 MHz and 32.768 MHz clock outputs that can be applied to the CS5378 CLK input.
  • Page 22: Microcontroller

    C8051F320 has dedicated pins for power and the USB connection, plus 25 general purpose I/O pins that connect to the various internal resources through a programmable crossbar. Hardware connections on CRD5378 limit how the blocks can operate, so the port mapping of microcontroller resources is detailed below.
  • Page 23 General purpose I/O Data in/out for debug interface P2.7 AIN- ADC input P2.6 AIN+ ADC input P2.5 GPIO General Purpose I/O (unused in CRD5378) P2.4 MODE2 CS5373A mode control P2.3 MODE1 CS5373A mode control P2.2 MODE0 CS5373A mode control Pin #...
  • Page 24: Rs-485 Telemetry

    Through the PC evaluation software, the microcontroller default firmware can be automatically flashed to the latest version without connecting an external programmer. To flash custom firmware, software tools and an inexpensive hardware programmer that connects to the C2 Debug Interface on CRD5378 is avail- able for purchase from Silicon Laboratories (DEBUGADPTR1-USB).
  • Page 25 2.3.3.1 CLK, SYNC Clock and synchronization telemetry signals into CRD5378 are received through RS-485 twisted pairs. These signals are required to be distributed through the external system with minimal jitter and timing skew, and so are normally driven through high-speed bus connections.
  • Page 26: Uart Connection

    I2C Bypass Switch Control BYP_EN When CRD5378 is used in a distributed measurement network, each node must have a unique address. This address is used to transmit individual configuration commands and tag the source of returned con- version data. Address assignment can be either dynamic or static, depending how the telemetry system is to be implemented.
  • Page 27: External Connector

    Linear voltage regulators create the positive and negative analog power supply voltages to the analog components on CRD5378. These regulate the +3.3 V and -3.3 V power supply inputs to create the +2.5 V and -2.5 V analog power supplies.
  • Page 28: Pcb Layout

    PCB Layout 2.5.1 Layer Stack CRD5378 layers 1 and 6 are dedicated as analog routing layers. All critical routes are on these two lay- ers. Some microcontroller digital routes are also included on these layers away from the analog signal routes.
  • Page 29: Figure 2. Differential Pair Routing

    CRD5378 plane. Differential traces are routed together with a minimal gap between them so that noise events affect them equally and are rejected as common mode noise. INA- INA- INA+ INA+ Figure 2. Differential Pair Routing Analog signal connections into the CS3301A/02A amplifiers are 2-wire IN+ and IN- differential pairs, and are routed as such.
  • Page 30: Bypass Capacitors

    CRD5378 2.5.3 Bypass Capacitors Each device power supply pin includes 0.1 µF bypass capacitors placed as close as possible to the pin. Each power supply net includes at least 68 µF bulk capacitance as a charge well for transient current loads.
  • Page 31: Software Description

    CRD5378 3. SOFTWARE DESCRIPTION Menu Bar The menu bar is always present at the top of the software panels and provides typical File and Help pull- down menus. The menu bar also selects the currently displayed panel. Control Description File Load Data Set Loads a data set from disk.
  • Page 32: About Panel

    CRD5378 About Panel The About panel displays copyright information for the Cirrus Seismic Evaluation software. Click OK to exit this panel. Select Help About from the menu bar to display this panel. DS639RD2...
  • Page 33: Setup Panel

    CRD5378 Setup Panel The Setup panel initializes the evaluation system to perform data acquisition. It consists of the following sub-panels and controls. • USB Port • Digital Filter • Analog Front End • Test Bit Stream • Gain/Offset • Data Capture •...
  • Page 34: Usb Port

    CRD5378 3.3.1 USB Port The USB Port sub-panel sets up the USB communication interface between the PC and the target board. Control Description Open Target Open USB communication to the target board and read the board name and micro- controller firmware version. When communication is established, the name of this control changes to ‘Close Target’...
  • Page 35: Digital Filter

    CRD5378 3.3.2 Digital Filter The Digital Filter sub-panel sets up the digital filter configuration options. By default the Digital Filter sub-panel configures the system to use on-chip coefficients and test bit stream data. The on-chip data can be overwritten by loading custom coefficients and test bit stream data from the Customize sub-panel on the Control panel.
  • Page 36: Analog Front End

    1x, 2x, 4x, 8x, 16x, 32x, or 64x can be selected and are con- trolled together. Selects how the DAC_BUF to INA analog switches are enabled when connected to the CRD5376. This control is not applicable to the CRD5378 and is disabled. 3.3.4 Test Bit Stream The Test Bit Stream sub-panel configures test bit stream (TBS) generator parameters.
  • Page 37: Gain/Offset

    CRD5378 3.3.5 Gain/Offset The Gain / Offset sub-panel controls the digital filter GAIN and OFFSET registers for each channel. The OFFSET and GAIN registers can be manually written with any 24-bit 2’s complement value from 0x800000 to 0x7FFFFF. The USEGR, USEOR, ORCAL, and EXP[4:0] values enable gain correction, off- set correction, and offset calibration in the digital filter.
  • Page 38: Data Capture

    CRD5378 3.3.6 Data Capture The Data Capture sub-panel collects samples from the target board and sets analysis parameters. When the Capture button is pressed, the requested number of samples are collected from the target board through the USB port. The maximum number of samples that can be collected is 1,048,576 (1M). The number of samples per channel should be a power of two for the analysis FFT routines to work properly.
  • Page 39: External Macros

    CRD5378 3.3.7 External Macros Macros are generated within the Macros sub-panel on the Control panel. Once a macro has been built it can either be saved with a unique macro name to be run within the Macros sub-panel, or saved as an external macro and be associated with one of the External Macro buttons.
  • Page 40: Analysis Panel

    CRD5378 Analysis Panel The Analysis panel is used to display the analysis results on collected data. It consists of the following controls. • Test Select • Statistics • Plot Enable • Cursor • Zoom • Refresh • Harmonics • Spot Noise •...
  • Page 41: Test Select

    CRD5378 3.4.1 Test Select The Test Select control sets the type of analysis to be run on the collected data set. Control Description Time Domain Runs a min / max calculation on the collected data set and then plots sample data value vs.
  • Page 42: Statistics

    CRD5378 3.4.2 Statistics The Statistics control displays calculated statistics for the selected analysis channel. For multichannel data captures, only one channel of calculated statistics are displayed at a time and is selected using the Statistics channel control. Errors that affect statistical calculations will cause the Plot Error control to appear. Information about er- rors on specific channels can be accessed by enabling the plot of the channel using the Plot Enable con- trol and then accessing the Plot Error controls.
  • Page 43: Zoom

    CRD5378 When using the Zoom function, the Cursor is used to select the corners of the area to zoom. 3.4.4 Zoom The ZOOM function allows an area on the graph to be expanded. To use the zoom function, click the ZOOM button and select the box corners of the area on the graph to expand.
  • Page 44: Control Panel

    CRD5378 Control Panel The Control panel is used to write and read register settings and to send commands to the digital filter. It consists of the following sub-panels and controls. • DF Registers • DF Commands • SPI1 • Macros •...
  • Page 45: Df Registers

    CRD5378 3.5.1 DF Registers The DF Registers sub-panel writes and reads registers within the digital filter. Digital filter registers con- trol operation of the digital filter and the included hardware peripherals, as described in the digital filter data sheet. Control...
  • Page 46: Macros

    CRD5378 3.5.4 Macros The Macros sub-panel is designed to write a large number of registers with a single command. This al- lows the target evaluation system to be quickly set into a specific state for testing. The Register control gives access to both digital filter registers and SPI1 registers. These registers can be written with data from the Data control, or data can be read and output to a text window.
  • Page 47: Customize

    CRD5378 3.5.6 Customize The Customize sub-panel sends commands to upload custom FIR and IIR filter coefficients, upload cus- tom test bit stream data, start the digital filter, stop the digital filter, and write/read custom EEPROM con- figuration files to the on-board boot EEPROM. Example data files are included in a sub-directory of the software installation.
  • Page 48: Bill Of Materials

    CRD5378 4. BILL OF MATERIALS DS639RD2...
  • Page 49: Layer Plots

    CRD5378 5. LAYER PLOTS DS639RD2...
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  • Page 57: Schematics

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