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Altera_Forum
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20 years ago

How to define the width of the pulse in IRQ?

hello everyone:

How to define the width of the pulse in IRQ,i use the "level" mode. thank you !

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    Hello,

    The IRQ line should be set by the interrupt source and cleared by the interrupt handler itself; just doing a pulse A) doesn&#39;t guarantee the interrupt will be recognised and http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/cool.gif if the pulse is too long, the interrupt handler could be called more times than you expect.
  • Altera_Forum's avatar
    Altera_Forum
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    --- Quote Start ---

    originally posted by steve360@Jun 15 2005, 06:52 AM

    hello,

    the irq line should be set by the interrupt source and cleared by the interrupt handler itself; just doing a pulse a) doesn&#39;t guarantee the interrupt will be recognised and http://forum.niosforum.com/work2/style_emoticons/<#emo_dir#>/cool.gif if the pulse is too long, the interrupt handler could be called more times than you expect.

    --- Quote End ---

    steve360,thank you.but i can&#39;t find the information of this problem,is it the same as common MCU?can you tell me how can i find the information.!
  • Altera_Forum's avatar
    Altera_Forum
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    If you are using the PIO in level mode, there is no way to guarantee that the interrupt will be active for any period of time. If you require knowledge that the state transitioned and/or don&#39;t want to have unknown cause interrupts, you will need to use the edge interrupt option of the PIO.