Digi BL1800 user manual Spectrum Spreader

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3.8.3 Spectrum Spreader

Jackrabbit boards that carry the CE mark have a Rabbit 2000 microprocessor that features a spectrum spreader, which helps to mitigate EMI problems. By default, the spectrum spreader is on automatically for Jackrabbit BL1810 and BL1820 boards that carry the CE mark when used with Dynamic C 7.32 or later versions, but the spectrum spreader may also be turned off or set to a stronger setting. The spectrum spreader settings may be changed through a simple configuration macro as shown below.

1.Select the “Defines” tab from the Dynamic C Options > Project Options menu.

2.Normal spreading is the default, and usually no entry is needed. If you need to specify normal spreading, add the line

ENABLE_SPREADER=1

For strong spreading, add the line

ENABLE_SPREADER=2

To disable the spectrum spreader, add the line

ENABLE_SPREADER=0

NOTE: The strong spectrum-spreading setting is not recommended since it may limit the maximum clock speed or the maximum baud rate. It is unlikely that the strong set- ting will be used in a real application.

3.Click OK to save the macro. The spectrum spreader will now remain off whenever you are in the project file where you defined the macro.

The spectrum spreader is off by default for Jackrabbit BL1800 models, and needs to be enabled for them to be CE-compliant. To allow the flash memory and RAM chips to accommodate the occasional higher frequencies associated with the spectrum spreader being turned on for the Jackrabbit BL1800 models only, you will need at least one wait state for both the flash memory and the RAM. The strong spectrum-spreading setting is not needed for any Jackrabbit board.

The number of wait states is specified in the following code from the LIB\BOARDTYPES library. (There are 0 wait states by default.)

#ifndef NUM_RAM_WAITST #define NUM_RAM_WAITST 0

#endif

#ifndef NUM_FLASH_WAITST #define NUM_FLASH_WAITST 0

#endif

There is no spectrum spreader functionality for Jackrabbit boards that do not carry the CE mark or when using any Jackrabbit with a version of Dynamic C prior to 7.30.

User’s Manual

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Contents Programmable Single-Board Computer Jackrabbit BL1800Digi International Inc TrademarksTable of Contents Index Schematics Introduction FeaturesDevelopment and Evaluation Tools Jackrabbit FeaturesHow to Use This Manual Additional Product InformationOnline Documentation CE Compliance ImmunityEmissions Safety Design Guidelines GeneralInterfacing the Jackrabbit to Other Devices Jackrabbit BL1800 Getting Started Development Kit ContentsDevelopment Hardware Connections Attach Jackrabbit to Prototyping Board BoardAssemble AC Adapter Connect Programming CableConnect Power Installing Dynamic C Run a Sample Program TroubleshootingWhere Do I Go From Here? Real-Time ClockTechnical Support BL1800 SubsystemsHeaders Jackrabbit PinoutsDigital Inputs Digital Inputs/OutputsHV3 Sourcing Output Digital OutputsConfigurable High-Current Output Changing HV3 to a Sinking Output Bidirectional I/OA/D Converter Schematic Diagram of A/D ConverterJackrabbit BL1800 D/A Converters Schematic Diagram of D/A Converters1 DA1 V ⋅ 1 e RCTypical DA1 Voltages for Various Duty Cycles Typical DA0 Voltages for Various Duty Cycles 2 DA0User’s Manual Serial Communication 1 RS-2322 RS-485 Ground recommended 485 R16 Programming PortUser’s Manual Programming Cable Changing Between Program Mode and Run ModeMemory SramFlash Eprom Other Hardware External InterruptsClock Doubler Spectrum Spreader Jackrabbit BL1800 An Overview of Dynamic C Software ReferenceJackrabbit BL1800 Jackrabbit Sample Programs Sample ProgramsSample Program DEMOJR1.C DEMOJR1.CWatch Expression Break Point Single-SteppingSummary of Features Editing the ProgramWatching Variables Dynamically User’s Manual Other Sample Programs Illustrating Digital I/O R/W pin and DB0-DB3 on 3 RS-232 Serial Communication Sample Programs 4 RS-485 Serial Communication Sample Program Cooperative Multitasking Int vswitch Advantages of Cooperative Multitasking 1 I/O Drivers Jackrabbit Function CallsVoid digOutint channel, int value Void anaOutint channel, int value Void anaInint channel, int *value Serial Communication Drivers Upgrading Dynamic C Patches and Bug FixesAdd-On Modules Appendix A. Specifications Figure A-1shows the mechanical dimensions for the Jackrabbit Electrical and Mechanical SpecificationsTable A-1. Jackrabbit Board Specifications Exclusion Zones Exclusion ZoneFigure A-3. User Board Footprint for Jackrabbit Figure A-4. Location of Jackrabbit Configurable Positions Jumper ConfigurationsTable A-2. Jackrabbit Jumper Configurations Conformally coated area Conformal CoatingJackrabbit Use of Rabbit 2000 Parallel PortsTable A-3. Jackrabbit Pinout Configurations PD0 PD1 Jackrabbit BL1800 Appendix B. Prototyping Board Prototyping Board Overview Jackrabbit Connectors User LEDs BuzzerPrototyping Board Features Top Side Mechanical Dimensions and LayoutTop Side Using the Prototyping BoardRelay Demonstration BoardExisting Top Side Prototyping BoardPE0 VCC HV0 SM1 SM0 HV2 Stat Jackrabbit BL1800 Power Supplies Appendix C. Power ManagementDcin Current mA 950 mA·h = 5.4 years 20 µA Batteries and External Battery ConnectionsFigure C-5shows the Jackrabbit battery backup circuitry Battery Backup CircuitReset Generator Power to Vram SwitchChip Select Circuit Figure C-7shows a schematic of the chip select circuitJackrabbit BL1800 SMODE0 SMODE1 IndexRABDB01.C RABDB02.C Schematics