Supriya Ghosh (Editor)

Serial Vector Format

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Serial Vector Format (SVF) is a file format that contains boundary scan vectors to be sent to an electronic circuit using a JTAG interface. Boundary scan vectors consist of the following data:

  • Stimulus data: This is data to be sent to a device or electronic circuit
  • Expected response: This is the data the device or circuit is expected to send back if there is no error
  • Mask data: Defines which bits in the expected response are valid; other bits of the device's response are unknown and must be ignored when comparing the expected response and the data returned from the circuit
  • Additional information on how to send the data (e.g. maximum clock frequency)

    • The SVF standard was jointly developed by companies Texas Instruments and Teradyne. Control over the format has been handed off to boundary-scan solution provider ASSET InterTech. The most recent revision is Revision E.

    SVF files are used to transfer boundary scan data between tools. As an example a VHDL compiler may create an SVF file that is read by a tool for programming CPLDs.

    The SVF file is defined as an ASCII file that consists of a set of SVF statements. The maximum number of characters allowed on a line is 256, although one SVF statement can span more than one line. Each statement consists of a command and associated parameters. Each SVF statement is terminated by a semicolon. SVF is not case sensitive. Comments can be inserted into a SVF file after an exclamation point ‘!’ or a pair of slashes ‘//’. Either ‘//’ or ‘!’ will comment out the remainder of the line.

    SVF commands

  • ENDDR: Specifies default end state for DR scan operations.
  • ENDIR: Specifies default end state for IR scan operations.
  • FREQUENCY: Specifies maximum test clock frequency for IEEE 1149.1 bus operations.
  • HDR: (Header Data Register) Specifies a header pattern that is prepended to the beginning of subsequent DR scan operations.
  • HIR: (Header Instruction Register) Specifies a header pattern that is prepended to the beginning of subsequent IR scan operations.
  • PIO: (Parallel Input/Output) Specifies a parallel test pattern.
  • PIOMAP: (Parallel Input/Output Map) Maps PIO column positions to a logical pin.
  • RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified number of clocks or a specified time period.
  • SDR: (Scan Data Register) Performs an IEEE 1149.1 Data Register scan.
  • SIR: (Scan Instruction Register) Performs an IEEE 1149.1 Instruction Register scan.
  • STATE: Forces the IEEE 1149.1 bus to a specified stable state.
  • TDR: (Trailer Data Register) Specifies a trailer pattern that is appended to the end of subsequent DR scan operations.
  • TIR: (Trailer Instruction Register) Specifies a trailer pattern that is appended to the end of subsequent IR scan operations.
  • TRST: (Test ReSeT) Controls the optional Test Reset line.

    • References

    Serial Vector Format Wikipedia
    (Text) CC BY-SA