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Altera_Forum's avatar
Altera_Forum
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19 years ago

sopc builder uart baud rate ignored

I have a problem with 2 processors talking over an async serial link, one of which is a nios2. The nios' uart is set for 115k baud (and variable is ticked in the sopc uart page), yet it comes up at 38.4 in a hello world, modified to printf inside a for loop. The uart is being driven by a pll at 85MHz. How could a divide by 3 be getting into the clock line, or am I on wrong track?

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

    115k / 3 = 38.33k

    It looks like the frequency is divided 2 times by 3.

    Is your UART driven by the 85MHz or by a divided freq?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    19 years ago

    --- Quote Start ---

    originally posted by kentmacfarlane@Feb 12 2007, 07:09 AM

    i have a problem with 2 processors talking over an async serial link, one of which is a nios2. the nios' uart is set for 115k baud (and variable is ticked in the sopc uart page), yet it comes up at 38.4 in a hello world, modified to printf inside a for loop. the uart is being driven by a pll at 85mhz. how could a divide by 3 be getting into the clock line, or am i on wrong track?

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    Even tried to confirm with fixed baud rate?