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Altera_Forum's avatar
Altera_Forum
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12 years ago

Generating an ultrasonic (40 KHz) square pulse for a distance sensor with VHDL

May anyone give me a hint how to generate a square pulse with VHDL to transmit it in a transducer for a distance sensor.

Thanks

Francisco.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    12 years ago

    What's your fpga clock frequency?

    a-For example, if your fclk is 50MHz, count from 0 to 50MHz/40KHz=1250.

    b-add a comparator to the counter: when count<625 output is '1' else '0'.

    c-register the output to avoid glitches.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    12 years ago

    I is actually 50 MHz, yet I have a given clock divider so I have different possible outputs, such as: 1 MHz, 100KHz, 10KHz, 1KHz, 100Hz,and 1 Hz. Ok, Thanks