Camera LinkSpecifications of theCamera LinkInterface Standard forDigital Cameras andFrame GrabbersCamera Link SpecificationsOctober 2000AcknowledgementsParticipating CompaniesThe following companies contributed to the development and definition ofthe Camera Link standard.•Basler•Cognex•Coreco•DALSA•Data Translation•Datacube•EPIX•Euresys•Foresight Imaging•Integral Technologies•Matrox•National Instruments•PULNiX AmericaRights and TrademarksPULNiX America, Inc., as chair of this ad hoc Camera Link committee, hasapplied for U.S. trademark protection for the term "Camera Link" to secureit for the mutual benefit of industry members. PULNiX will issue aperpetual royalty-free license to any industry member (includingcompetitors) for the use of the "Camera Link" trademark on the conditionthat it is used only in conjunction with products that are fully compliant tothis standard. PULNiX will not require licensed users of the trademark tocredit PULNiX with ownership.3M™ is a trademark of the 3M Company.Channel Link™ is a trademark of National Semiconductor.Flatlink™ is a trademark of Texas Instruments.Panel Link™ is a trademark of Silicon Image.About this DocumentThe following specifications provide a framework for Camera Linkcommunication. The specifications are deliberately defined to be open,allowing camera and frame grabber manufacturers to differentiate theirproducts. Additional recommendations may be added at a later date, whichwill not affect the accuracy of the information in this document.ContentsAcknowledgementsParticipating Companies (ii)Rights and Trademarks (ii)About this DocumentChapter 1Camera LinkIntroduction....................................................................................................................1-1 LVDS Technical Description.........................................................................................1-1 Channel Link..................................................................................................................1-2 Technology Benefits......................................................................................................1-3 Smaller Connectors and Cables.......................................................................1-3High Data Transmission Rates........................................................................1-3 Chapter 2Camera Signal RequirementsVideo Data.......................................................................................................2-1Camera Control Signals...................................................................................2-1Communication...............................................................................................2-2Power...............................................................................................................2-2 Chapter 3Port AssignmentsPort Definition.................................................................................................3-1 Chapter 4Bit AssignmentsChapter 5Camera Link ConnectionsMDR 26-pin Connector...................................................................................5-1Camera Link Cable Pinout..............................................................................5-2Shielding Recommendations...........................................................................5-3ContentsAppendix AChipset CriteriaAppendix BAPI FunctionsAppendix CBit Assignments According to ConfigurationAppendix DCamera Link Cabling InformationFiguresFigure 1-1.Channel Link Operation........................................................................1-2 Figure 3-1.Data Routing for Base, Medium, and Full Configurations...................3-2 Figure 3-2.Block Diagram of Base, Medium, and Full Configuration ..................3-3 Figure 5-1.Camera Link Cable...............................................................................5-1 Figure D-1.Dimensions of 3M Connector...............................................................D-1 Figure D-2.3M Part Number Ordering Information................................................D-3 TablesTable 3-1.Port Assignments According to Configuration.....................................3-1 Table 4-1.Camera Link Bit Assignment................................................................4-1 Table patible National Semiconductor Parts...........................................A-1 Table C-1.Bit Assignments for Base Configuration..............................................C-1 Table C-2.Bit Assignment for Medium Configuration..........................................C-2 Table C-3.Bit Assignment for Full Configuration.................................................C-4 Table D-1.Shell Options.........................................................................................D-3 Table D-2.3M Boardmount Receptacle Part Numbers..........................................D-41 Camera LinkIntroductionCamera Link is a communication interface for vision applications. Theinterface extends the base technology of Channel Link to provide aspecification more useful for vision applications.For years, the scientific and industrial digital video market has lacked astandard method of communication. Both frame grabbers and cameramanufacturers developed products with different connectors, making cableproduction difficult for manufacturers and very confusing for consumers. Aconnectivity standard between digital cameras and frame grabbers is longoverdue and will become even more necessary as data rates continue toincrease.Increasingly diverse cameras and advanced signal and data transmissionshave made a connectivity standard like Camera Link a necessity. TheCamera Link interface will reduce support time, as well as the cost of thatsupport. The standard cable will be able to handle the increased signalspeeds, and the cable assembly will allow customers to reduce their coststhrough volume pricing.LVDS Technical DescriptionLow Voltage Differential Signaling (LVDS) is a high-speed, low-powergeneral purpose interface standard. The standard, known asANSI/TIA/EIA-644, was approved in March 1996. LVDS uses differentialsignaling, with a nominal signal swing of 350 mV differential. The lowsignal swing decreases rise and fall times to achieve a theoretical maximumtransmission rate of 1.923 Gbps into a loss-less medium. The low signalswing also means that the standard is not dependent on a particular supplyvoltage. LVDS uses current-mode drivers, which limit power consumption.The differential signals are immune to ±1 V common volt noise.Channel LinkNational Semiconductor developed the Channel Link technology as asolution for flat panel displays, based on LVDS for the physical layer. Thetechnology was then extended into a method for general purpose datatransmission. Channel Link consists of a driver and receiver pair. Thedriver accepts 28 single-ended data signals and a single-ended clock. Thedata is serialized 7:1, and the four data streams and a dedicated clock aredriven over five LVDS pairs. The receiver accepts the four LVDS datastreams and LVDS clock, and then drives the 28 bits and a clock to theboard. Figure1-1 illustrates Channel Link operation.Figure 1-1. Channel Link OperationTechnology BenefitsSmaller Connectors and CablesChannel Link’s transmission method requires fewer conductors to transferdata. Five pairs of wires can transmit up to 28 bits of data. These wiresreduce the size of the connector, allowing smaller cameras to bemanufactured.High Data Transmission RatesThe data transmission rates of the Channel Link chipset (up to 2.38Gbits/s)support the current trend of increasing transfer speeds.2 Camera Signal RequirementsThis section provides definitions for the signals used in the Camera Linkinterface. The standard Camera Link cable provides camera control signals,serial communication, and video data.Video DataThe Channel Link technology is integral to the transmission of video data.Image data and image enables are transmitted on the Channel Link bus.Four enable signals are defined as:•FV AL—Frame V alid (FV AL) is defined HIGH for valid lines.•LV AL—Line V alid (LV AL) is defined HIGH for valid pixels.•DV AL—Data V alid (DV AL) is defined HIGH when data is valid.•Spare— A spare has been defined for future use.All four enables must be provided by the camera on each Channel Linkchip. All unused data bits must be tied to a known value by the camera.For more information on image data bit allocations, see Section 3,Bit Assignments, and Appendix C, Bit Assignments According toConfiguration.Camera Control SignalsFour LVDS pairs are reserved for general-purpose camera control. Theyare defined as camera inputs and frame grabber outputs. Cameramanufacturers can define these signals to meet their needs for a particularproduct. The signals are:•Camera Control 1 (CC1)•Camera Control 2 (CC2)•Camera Control 3 (CC3)•Camera Control 4 (CC4)CommunicationTwo LVDS pairs have been allocated for asynchronous serialcommunication to and from the camera and frame grabber. Cameras andframe grabbers should support at least 9600 baud. These signals are•SerTFG—Differential pair with serial communications to the framegrabber.•SerTC—Differential pair with serial communications to the camera.The serial interface will have the following characteristics: one start bit, onestop bit, no parity, and no handshaking.It is recommended that frame grabber manufacturers supply both a userinterface and a software application programmming interface (API) forusing the asynchronous serial communication port. The user interface willconsist of a terminal program with minimal capabilities of sending andreceiving a character string and sending a file of bytes. The software APIwill provide functions to enumerate boards and send or receive a characterstring. See Appendix B, API Functions,for a suggested softwareapplication program interface (API).PowerPower will not be provided on the Camera Link connector. The camera willreceive power through a separate cable. Each camera manufacturer willdefine their own power connector, current, and voltage requirements.3 Port AssignmentsThe Camera Link interface has three configurations. Since a singleChannel Link chip is limited to 28 bits, some cameras may require severalchips in order to transfer data efficiently. The naming conventions for thevarious configurations are:•Base—Single Channel Link chip, single cable connector.•Medium—Two Channel Link chips, two cable connectors.•Full—Three Channel Link chips, two cable connectors.Port DefinitionA port is defined as an 8-bit word. The Least Significant Bit (LSB) is bit 0,and the Most Significant Bit (MSB) is bit 7. The Camera Link interfaceutilizes the 8 ports of A-H.The following table shows the port assignment for the Base, Medium, andFull Configurations.Table 3-1. Port Assignments According to ConfigurationConfiguration Ports Supported Number of Chips Number of ConnectorsBase A, B, C11 Medium A, B, C, D, E, F22 Full A, B, C, D, E, F, G, H32Figure 3-1. Data Routing for Base, Medium, and Full Configurations The block diagram shown in Figure 3 illustrates the Base, Medium, and Full Configurations.Figure 3-2. Block Diagram of Base, Medium, and Full Configuration4Table 4-1. Camera Link Bit Assignment (Continued) Tx Input Signal Name28-bit Solution Pin Name Port B3, Port E3, Port H3TX/RX 12Port B4, Port E4, Port H4TX/RX 13Port B5, Port E5, Port H5TX/RX 14Port B6, Port E6, Port H6TX/RX 10Port B7, Port E7, Port H7TX/RX 11Port C0, Port F0TX/RX 15Port C1, Port F1TX/RX 18Port C2, Port F2TX/RX 19Port C3, Port F3TX/RX 20Port C4, Port F4TX/RX 21Port C5, Port F5TX/RX 22Port C6, Port F6TX/RX 16Port C7, Port F7TX/RX 175Camera Link Cable Pinout.Table 5-1. MDR-26 Connector AssignmentsMedium and Full ConfigurationsBase Configuration (with Camera Control and Serial Communication)Camera ConnectorFrameGrabberConnectorChannelLinkSignalCableNameCameraConnectorFrameGrabberConnectorChannelLinkSignal11innershield InnerShield11innershield1414innershield InnerShield1414innershield225Y0-PAIR1-225X0-1512Y0+PAIR1+1512X0+ 324Y1-PAIR2-324X1-1611Y1+PAIR2+1611X1+ 423Y2-PAIR3-423X2-1710Y2+PAIR3+1710X2+ 522Yclk-PAIR4-522Xclk-189Yclk+PAIR4+189Xclk+ 621Y3-PAIR5-621X3-198Y3+PAIR5+198X3+ 720100 ΩPAIR6+720SerTC+ 207terminated PAIR6-207SerTC-819Z0-PAIR7-819SerTFG-216Z0+PAIR7+216SerTFG+ 918Z1-PAIR8-918CC1-225Z1+PAIR8+225CC1+ 1017Z2-PAIR9+1017CC2+ 234Z2+PAIR9-234CC2-Shielding RecommendationsThe outer shield of the cable is tied to the connector shell. It isrecommended that the inner shell be tied to digital ground in cameras and tied through a resister to digital ground in the frame grabbers. It isrecommended that a 0 Ω resistor be installed in the factory. If necessary, that resistor can be removed in the field and replaced with a high-value resistor and parallel capacitor. Unused pairs should be terminated to 100Ω at their respective ends of the cable.NoteAll pairs are individually shielded with aluminum foil. Pair shields are wrapped aluminum out and are in contact with four internal drains (digital ground). Outer braid and foil (chassis ground) are isolated from inner drains (digital ground).234Z2+PAIR9-234CC2-1116Zclk-PAIR10-1116CC3-243Zclk+PAIR10+243CC3+1215Z3-PAIR11+1215CC4+252Z3+PAIR11-252CC4-1313inner shield Inner Shield 1313inner shield 2626inner shieldInner Shield2626inner shieldTable 5-1. MDR-26 Connector Assignments (Continued)Medium and Full Configurations Base Configuration (with Camera Control and Serial Communication)Camera ConnectorFrame Grabber ConnectorChannel Link Signal Cable Name Camera ConnectorFrame Grabber ConnectorChannel Link SignalAChipset CriteriaCamera Link uses 28-bit Channel Link chips manufactured by National Semiconductor. Because of potential interface issues, chips that use a similar technology, such as Flatlink by Texas Instruments and Panel Link by Silicon Image, may not be compatible with the Camera Link interface. Receivers and drivers with different operating frequencies will interoperate over the frequency range that both support. The following table lists some compatible National Semiconductor parts.The pinout of the MDR 26 connector was chosen for optimal PWB trace routing using an LVDS driver/receiver pair for camera control signals. The following are the recommended National Semiconductor parts for the pair:DS90LV047 3.3 V transmitter DS90LV0483.3 VreceiverTable A-1. Compatible National Semiconductor PartsProduct Supply Voltage SpeedDS90CR281 5 V 40 MHz DS90CR282 5 V 40 MHz DS90CR283 5 V 66 MHz DS90CR284 5 V 66 MHz DS90CR285 3.3 V 66 MHz DS90CR286 3.3 V 66 MHz DS90CR286A 3.3 V 66 MHz DS90CR287 3.3 V 85 MHz DS90CR288 3.3 V 75 MHz DS90CR288A3.3 V85 MHzB API FunctionsA consistent, known API for asynchronous serial reading and writingallows camera vendors to write a frame grabber-independent,camera-specific configuration utility. The following API offers a solutionfor camera vendors that is easy for frame grabber manufacturers toimplement, regardless of the actual implementation methods used forasynchronous serial communication.All frame grabbers provide a .dll file named clser***.dll, where ***is specific to the frame grabber vendor. There are four functions withinthat .dll:•clSerialInit—Initialize the serial communication fora specific board.•clSerialRead—Read bytes from the camera.•clSerialWrite—Write bytes to the camera.•clSerialClose—Close the serial communication.clSerialInitFormatint clSerialInit(unsigned long serialIndex, void** serialRefPtr)PurposeThis function initializes the device referred to by serialIndex, and returns a pointer to aninternal serial reference structure.ParametersName Direction Description serialIndex input A zero-based index value. For nserial devices in the systemsupported by this library,serialIndex has a range of0to(n-1).serialRefPtr output Points to a value that contains, on asuccessful call, a pointer to thevendor-specific reference to thecurrent session.Return ValueA vendor-specific error value that follows these conventions:• A negative value indicates a fatal error.• A zero value indicates success.• A positive value indicates a warning.Formatint clSerialRead(void* serialRef, char* buffer,unsigned long* bufferSizeunsigned long serialTimeout)PurposeThis function reads the serial device referenced by serialRef.ParametersName Direction Description serialRef input The value obtained from theclSerialInit function.buffer output Points to a user-allocated buffer.Upon a successful call, buffercontains the data read from theserial device.bufferSize input/output Contains the buffer size indicatingthe maximum number of bytes thatthe buffer can accommodate. Upona successful call, bufferSizecontains the number of bytes readsuccessfully from the serial device.serialTimeout input Indicates the timeout inmilliseconds.Return ValueA vendor-specific error value that follows these conventions:• A negative value indicates a fatal error.• A zero value indicates success.• A positive value indicates a warning.Formatint clSerialWrite(void* serialRef, char* buffer,unsigned long* bufferSizeunsigned long SerialTimeout)PurposeThis function writes the data in the buffer to the serial device referenced by SerialRef. ParametersName Direction Description serialRef input The value obtained from theclSerialInit function.buffer input Contains data to write to the serialport.bufferSize input/output Contains the buffer size indicatingthe maximum number of bytes thatthe buffer can accommodate. Upona successful call, bufferSizecontains the number of bytes readsuccessfully from the serial device.serialTimeout input Indicates the timeout inmilliseconds.Return ValueA vendor-specific error value that follows these conventions:• A negative value indicates a fatal error.• A zero value indicates success.• A positive value indicates a warning.Formatvoid clSerialClose(void* serialRef)PurposeThis function closes the serial device and cleans up the resources associated with serialRef.Upon return, serialRef is no longer usable.ParametersName Direction Description serialRef input The value obtained from theclSerialInit function forclean up.Return ValueA vendor-specific error value that follows these conventions:• A negative value indicates a fatal error.• A zero value indicates success.• A positive value indicates a warning.Header FileThe following is an example of an appropriate header file for this API: #ifndef _CLSER____H_#define _CLSER____H_#ifndef CLSER___EXPORT#define CLSER___EXPORT __declspec(dllimport)#endif#ifndef CLSER___CC#define CLSER___CC __cdecl#endif#ifdef __cplusplusextern "C"{#endifCLSER___EXPORT int CLSER___CCclSerialInit(unsigned long serialIndex, void** serialRefPtr);CLSER___EXPORT int CLSER___CCclSerialRead(void* serialRef, char* buffer,unsigned long* bufferSize, unsigned long serialTimeout);CLSER___EXPORT int CLSER___CCclSerialWrite(void* serialRef, char* buffer, unsigned long* bufferSize, unsigned long serialTimeout);CLSER___EXPORT void CLSER___CCclSerialClose(void* serialRef);#ifdef __cplusplus}#endif#endifNote Using a single .dll file prevents the user from accessing driver software frommultiple vendors at the same time; therefore, camera vendors using this API must load all .dll files with the name clser*.dll on the system and then provide a method for the user to select the correct vendor for the board they are using. The camera vendor should use LoadLibrary and GetProcAddress to find these functions. The camera vendors should also provide a way for users to select a particular frame grabber, and then use clSerialRead and clSerialWrite to communicate with the camera attached to their board.CBit Assignments According to ConfigurationTable C-1. Bit Assignments for Base ConfigurationBase ConfigurationPort/bit 8-bit x1~3*10-bit x1~212-bit x1~214-bit x 116-bit x 124-bitRGBPort A0A0A0A0A0A0R0 Port A1A1A1A1A1A1R1 Port A2A2A2A2A2A2R2 Port A3A3A3A3A3A3R3 Port A4A4A4A4A4A4R4 Port A5A5A5A5A5A5R5 Port A6A6A6A6A6A6R6 Port A7A7A7A7A7A7R7 Port B0B0A8A8A8A8G0 Port B1B1A9A9A9A9G1 Port B2B2nc A10A10A10G2 Port B3B3nc A11A11A11G3 Port B4B4B8B8A12A12G4 Port B5B5B9B9A13A13G5 Port B6B6nc B10nc A14G6 Port B7B7nc B11nc A15G7 Port C0C0B0B0nc nc B0 Port C1C1B1B1nc nc B1Port C2C2B2B2nc nc B2Port C3C3B3B3nc nc B3Port C4C4B4B4nc nc B4Port C5C5B5B5nc nc B5Port C6C6B6B6nc nc B6Port C7C7B7B7ncncB7* If only using a single channel, use Port A. If using two channels, use Port A and B.Table C-2. Bit Assignment for Medium ConfigurationMedium ConfigurationPort/bit 8-bit x 410-bit x 3~412-bit x 3~430-bit RGB36-bit RGBPort A0A0A0A0R0R0Port A1A1A1A1R1R1Port A2A2A2A2R2R2Port A3A3A3A3R3R3Port A4A4A4A4R4R4Port A5A5A5A5R5R5Port A6A6A6A6R6R6Port A7A7A7A7R7R7Port B0B0A8A8R8R8Port B1B1A9A9R9R9Port B2B2nc A10nc R10Port B3B3nc A11nc R11Port B4B4B8B8B8B8Table C-1. Bit Assignments for Base Configuration (Continued)Base ConfigurationPort/bit 8-bit x 1~3*10-bit x 1~212-bit x 1~214-bit x 116-bit x 124-bit RGBMedium ConfigurationPort/bit8-bit x 410-bit x 3~412-bit x 3~430-bit RGB 36-bit RGB Port B5B5B9B9B9B9 Port B6B6nc B10nc B10 Port B7B7nc B11nc B11 Port C0C0B0B0B0B0 Port C1C1B1B1B1B1 Port C2C2B2B2B2B2 Port C3C3B3B3B3B3 Port C4C4B4B4B4B4 Port C5C5B5B5B5B5 Port C6C6B6B6B6B6 Port C7C7B7B7B7B7 Port D0D0D0D0nc nc Port D1D1D1D1nc nc Port D2D2D2D2nc nc Port D3D3D3D3nc nc Port D4D4D4D4nc nc Port D5D5D5D5nc nc Port D6D6D6D6nc nc Port D7D7D7D7nc nc Port E0nc C0C0G0G0 Port E1nc C1C1G1G1 Port E2nc C2C2G2G2 Port E3nc C3C3G3G3 Port E4nc C4C4G4G4 Port E5nc C5C5G5G5Medium ConfigurationPort/bit8-bit x 410-bit x 3~412-bit x 3~430-bit RGB 36-bit RGB Port E6nc C6C6G6G6 Port E7nc C7C7G7G7 Port F0nc C8C8G8G8 Port F1nc C9C9G9G9 Port F2nc nc C10nc G10 Port F3nc nc C11nc G11 Port F4nc D8D8nc nc Port F5nc D9D9nc nc Port F6nc nc D10nc nc Port F7nc nc D11nc ncTable C-3. Bit Assignment for Full ConfigurationFull ConfigurationPort/bit8-bit x 8Port/bit8-bit x 8Port A0A0Port E0E0Port A1A1Port E1E1Port A2A2Port E2E2Port A3A3Port E3E3Port A4A4Port E4E4Port A5A5Port E5E5Port A6A6Port E6E6Port A7A7Port E7E7Port B0B0Port F0F0Port B1B1Port F1F1Port B2B2Port F2F2Table C-3. Bit Assignment for Full Configuration (Continued)Full ConfigurationPort/bit8-bit x 8Port/bit8-bit x 8 Port B3B3Port F3F3 Port B4B4Port F4F4 Port B5B5Port F5F5 Port B6B6Port F6F6 Port B7B7Port F7F7 Port C0C0Port G0G0 Port C1C1Port G1G1 Port C2C2Port G2G2 Port C3C3Port G3G3 Port C4C4Port G4G4 Port C5C5Port G5G5 Port C6C6Port G6G6 Port C7C7Port G7G7 Port D0D0Port H0H0 Port D1D1Port H1H1 Port D2D2Port H2H2 Port D3D3Port H3H3 Port D4D4Port H4H4 Port D5D5Port H5 H5 Port D6D6Port H6H6 Port D7D7Port H7H7DOrdering InformationCable assemblies and boardmount receptacles are available from 3M. For more information on 3M products, see the 3M Web site at .Cable Assembly Part NumbersFigure D-2. 3M Part Number Ordering InformationTable D-1. Shell OptionsShell Option B C Thumbscrew Overmold Shell 1.58[40.2].55[14.0]Thumbscrew Shell Kit1.55[39.4].51[12.8]Boardmount Receptacle Part NumbersThe following table lists the 3M boardmount receptacle part numbers.Table D-2. 3M Boardmount Receptacle Part NumbersPart Number Type Mount N10226-52xxVC MDR 26 Right Angle Thru-hole10266-55G3VC MDR 26 Right Angle Thru-hole10226-6212VC MDR 26 Vertical Thru-hole10226-1A10VE MDR 26 Right Angle SMT10226-2200VE MDR 26 Vertical SMT。
