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Altera_Forum's avatar
Altera_Forum
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16 years ago

Can I use ALTPLL in Cyclone II in this way?

The clock in my project is transmitting by LVDS.

Can I use ALTPLL in Cyclone II in this way :

I connect clk+ to LVDSCLK0p, clk- to LVDSCLK0n, then I use a ALTPLL in my design, its output c0 connect to PLL1_OUT.

Is this right?

I think, the IO bank where LVDSCLK0p and PLL1_OUT in is the same one, can I use

a LVDS clock (in) and a normal clock (out) in this way .

thank you.

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    --- Quote Start ---

    Yes, it's correct.

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    Thank you!

    Is this mean I would put 3.3V to the VCCIO?
  • Altera_Forum's avatar
    Altera_Forum
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    o! thanks a lot. I got it. This information is so useful!

    --- Quote Start ---

    When Cyclone II dedicated clock input pins are configured for the LVDS or LVPECL I/O standard for input operations, the differential buffer is powered by VCCINT, not VCCIO. Thus, the VCCIO does not have to be 2.5V when you use LVDS or LVPECL I/O standards on the dedicated clock input pins for input operations.

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