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Altera_Forum's avatar
Altera_Forum
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11 years ago

PWM Schematic does not work

Dear helpful guys,

I am a newbie who has started working with Quartus...

In the appendix I have saved a picture of my schematic

and also the Altera application note

as PDF for the circuit I want to built and work with.

When I compile the circuit I get no errors and also I can write

the code to my Platform which uses an EP1C3T144C8N.

When I want to measure the PWM output signal I always measure

3,3V although I vary the input data which changes the duty cycle.

Is there something wrong with my circuit?

Can anybody tell me what is exactly meant by the speed grade 8N?

Thank you very much.

Best regards,

Funky Pi

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    11 years ago

    The schematic picture is very low res and I can't see anything.

    If you want help, please post a better quality image and possibly answer to these questions:

    - How are you driving input data?

    - how are you measuring pwm output?

    - are you sure the signals are assigned to proper fpga pins?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Hi, thanks for your reply.

    I have added the schematic as PDF, I hope it is better now.

    Concerning question

    1) I have connected Pin 120 to 127 to GND or 3,3V

    2) With the oscilloscope (USB oscilloscope from Hantek with B=20 MHz and 40 MSamples/s)

    3) I have assigned the Pinning with the Quartus Pin Planner so I think this should be correct

    or do you know any way how to control this?

    Thanks.

    Best regards,

    Funky P.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Check the sample enable signal and possibly route out the q3 clock. Verify they are as expected

    You said you don't have any error in compilation: check if you have any relevant warning, too
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Thanks.

    With some small modifications I got it working now on Quartus Version 11.

    The working schematic can be found in the appendix.

    Best regards,

    Funky Pi