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Measure Timing

Measure timing of pixel control bus input

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  • Measure Timing block

Libraries:
Vision HDL Toolbox / Utilities

Description

The Measure Timing block measures the timing parameters of a video stream. This block is for use in Simulink® simulation only and does not support HDL code generation.

The Vision HDL Toolbox™ streaming pixel protocol implements the timing of a video system, including inactive intervals between frames. These inactive intervals are called blanking intervals. Many Vision HDL Toolbox blocks require minimum blanking intervals. For more information, see Configure Blanking Intervals. You can use the timing parameter measurements from this block to check that your video stream meets these requirements. If you manipulate the control signals of your video stream, you can use this block to verify the resulting signals.

To determine the parameters of each frame, the block measures the time steps between the control signals on the bus.

Logic Analyzer waveform that shows six time measurements between control signals

  • 1 — Active pixels per line

  • 2 — Active lines per frame (count hStart pulses)

  • 3 — Total pixels per line

  • 4 — Total lines per frame (cycles divided by total pixels per line)

  • 5 — Horizontal blanking

  • 6 — Vertical blanking (cycles, minus horizontal blanking, divided by total pixels per line)

For details on the pixel control bus and the dimensions of a video frame, see Streaming Pixel Interface.

Note

Measurements from the first simulated frame are incorrect because some parameters require measurements between frames. Simulate at least two frames before using the results.

Ports

Input

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The pixelcontrol bus contains five signals. The signals describe the validity of the pixel and its location in the frame. For more information, see Pixel Control Bus.

Data Types: bus

Output

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Number of pixels in each line of the active video frame, returned as a scalar. This value is measured by counting valid pixels between hStart and hEnd. See marker 1 in the diagram.

Data Types: double

Number of lines in the active video frame, returned as a scalar. This value is measured by counting the hStart pulses between vStart and vEnd. See marker 2 in the diagram.

Data Types: double

Number of pixels in each line, including the horizontal blanking interval, returned as a scalar. This value is measured by counting the number of valid pixels between two hStart pulses. See marker 3 in the diagram.

Data Types: double

Number of lines in the frame, including the vertical blanking interval, returned as a scalar. This value is measured by counting the number of valid pixels between two vEnd pulses, divided by totalPixels. See marker 4 in the diagram.

Data Types: double

Number of inactive pixels between lines of a frame, returned as a scalar. This value is measured by counting invalid cycles between hEnd and the next hStart. See marker 5 in the diagram.

Data Types: double

Number of inactive lines between frames, returned as a scalar. This value is measured by counting invalid cycles between vEnd and the next vStart, subtracting horizBlank, and then dividing by totalPixels. See marker 6 in the diagram.

Data Types: double

Extended Capabilities

Version History

Introduced in R2016b

See Also

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