How IP Addresses are Used | Digi RCM4000 guide

6.2.2 How IP Addresses are Used

The actual hardware connection via an Ethernet uses Ethernet adapter addresses (also called MAC addresses). These are 48-bit addresses and are unique for every Ethernet adapter manufactured. In order to send a packet to another computer, given the IP address of the other computer, it is first determined if the packet needs to be sent directly to the other computer or to the gateway. In either case, there is an Ethernet address on the local network to which the packet must be sent. A table is maintained to allow the protocol driver to determine the MAC address corresponding to a particular IP address. If the table is empty, the MAC address is determined by sending an Ethernet broadcast packet to all devices on the local network asking the device with the desired IP address to answer with its MAC address. In this way, the table entry can be filled in. If no device answers, then the device is nonexistent or inoperative, and the packet cannot be sent.

Some IP address ranges are reserved for use on internal networks, and can be allocated freely as long as no two internal hosts have the same IP address. These internal IP addresses are not routed to the Internet, and any internal hosts using one of these reserved IP addresses cannot communicate on the external Internet without being connected to a host that has a valid Internet IP address. The host would either translate the data, or it would act as a proxy.

Each RCM4000 RabbitCore module has its own unique MAC address, which consists of the prefix 0090C2 followed by a code that is unique to each RCM4000 module. For exam- ple, a MAC address might be 0090C2C002C0.

TIP: You can always obtain the MAC address on your module by running the sample program DISPLAY_MAC.C from the SAMPLES\TCPIP folder.

68	RabbitCore RCM4000

Image 74

Digi RCM4000 user manual How IP Addresses are Used

Contents

RabbitCore RCM4000 Trademarks Rabbit Semiconductor Table of Contents Software Reference Appendix C. Power Supply 109 RabbitCore RCM4100 Introduction Feature RCM4000 RCM4010 RCM4000 FeaturesRCM4000 Features Advantages of the RCM4000 Development and Evaluation Tools 1 RCM4000 Development Kit Software Online Documentation RabbitCore RCM4000 Install Dynamic C Getting Started Hardware Connections Prepare the Prototyping Board for Development Attach Module to Prototyping Board Prototyping Board AC Adapter Connect Programming Cable Connect Power Run a Sample Program TroubleshootingRun a Sample Program Where Do I Go From Here? Technical Support RabbitCore RCM4000 Running Sample Programs Introduction Sample Programs User’s Manual Use of Nand Flash RCM4000 only Click OK or Close to exit the various dialog boxes Serial Communication User’s Manual 3 A/D Converter Inputs RCM4000 only Real-Time Clock Hardware Reference RabbitCore Module RCM4000 Digital Inputs and Outputs Shows the RCM4000 pinouts for header J3 4000 RCM4000 Pinout Configurations Pin Pin Name Default Use Alternate Use TXD PC0 PE1 Memory I/O Interface Other Inputs and Outputs Serial Ports Rabbit 4000 Serial Port and Clock PinsSerial Communication Ethernet Port RJ-45 Ethernet Port Pinout Programming Port Changing Between Program Mode and Run Mode Programming Cable Standalone Operation of the RCM4000 A/D Converter RCM4000 only Resistor Divider Network for Analog Inputs It is not referenced to 1 A/D Converter Power Supply Analog Supply Circuit Spectrum Spreader Other HardwareClock Doubler Flash Eprom MemorySram Nand Flash RabbitCore RCM4000 Software Reference More About Dynamic C RabbitCore RCM4000 Serial Communication Drivers Dynamic C Function CallsDigital I/O Sram Use RabbitCore RCM4000 Prototyping Board Functions Board Initialization Void timedAlertunsigned long timeout Alerts ADS7870 Signal ADS7870 State RCM3400 Function/State Analog Inputs RCM4000 only On write operations Data value on read operations Unsigned int anaInDriverunsigned int cmd, unsigned int len Gain Code Multiplier AnaInConfig, anaIn, brdInit Single Diff Gain Code Multiplier Voltage Range ×10 ×16 ×20 126 Applies to Prototyping Board If successful If not able to make calibration constants Float anaInVoltsunsigned int channel, unsigned int gaincode Channel Code Single-Ended Voltage Range † Input Lines Float anaInDiffunsigned int channel, unsigned int gaincode Float anaInmAmpsunsigned int channel Channel Code 20 mA Input Lines Allchan Gain Code Voltage Range +AIN7 AIN6 Gain Code Voltage Range Upgrading Dynamic C Add-On Modules RabbitCore RCM4000 Using the TCP/IP Features TCP/IP Connections RabbitCore RCM4000 TCP/IP Primer on IP Addresses Typical Corporate Network IP Addresses Explained How IP Addresses are Used Dynamically Assigned Internet Addresses Placing Your Device on the Network Direct Connection Direct Connection Using a HubRunning TCP/IP Sample Programs How to Set IP Addresses in the Sample Programs How to Set Up your Computer for Direct Connect Direct Connection PC to RCM4000 Module Run the PINGME.C Sample Program Running Additional Sample Programs With Direct Connect Where Do I Go From Here? RabbitCore RCM4000 Appendix A. RCM4000 Specifications Electrical and Mechanical Characteristics Dia × Exclusion Zone Table A-1. RCM4000 Specifications Parameter RCM4000 RCM4010 Ten 8-bit timers 6 cascadable from the first Parameter Test Conditions Table A-2 Converter Specifications1 A/D Converter Headers Figure A-3. User Board Footprint for RCM4000 Symbol Parameter Maximum Rating Rabbit 4000 DC CharacteristicsTable A-4 .3 Volt DC Characteristics Symbol Parameter Min Typ Max Table A-5. Capacitance of Rabbit 4000 I/O Ports I/O Buffer Sourcing and Sinking LimitBus Loading Table A-6. External Capacitive Bus Loading -40C to +85C Iord 30 pF 60 pF 90 pF Ns setting No dbl / dbl Table A-8. Preliminary Data and Clock DelaysOutput Delay Clock to Address Worst-Case Conformal Coating Conformally coated Area Header Description Pins Connected Factory Default Jumper ConfigurationsTable A-9. RCM4000 Jumper Configurations RabbitCore RCM4000 Appendix B. Prototyping Board Current Measurement Headers RCM4000 Prototyping Board Features RabbitCore RCM4000 Mechanical Dimensions and Layout 935 Parameter Specification Power SupplyTable B-1. Prototyping Board Specifications Using the Prototyping Board Signals Pin Pin Name Prototyping Board Use Adding Other Components Measuring Current Draw 3.1 A/D Converter Inputs Analog Features RCM4000 onlyTable B-3. Positive A/D Converter Input Voltage Ranges Table B-4. Differential Voltage Ranges 3.3 A/D Converter Calibration Mode Read CalibrateThermistor Input Table B-5. Prototyping Board Serial Port Configurations Serial Port Header Default Use Alternate Use 4.1 RS-232 Prototyping Board Jumper Configurations Table B-6. RCM3400 Prototyping Board Jumper Configurations JP5 LN4IN-LN6IN 108 Battery-Backup Circuits Appendix C. Power SupplyPower Supplies Reset Generator 165 mA·h = 2.5 years User’s Manual 111 112 Index SMODE0 SMODE1 ADCALALL.C User’s Manual 115 116 Schematics