Forum Discussion
3 Replies
- Altera_Forum
Honored Contributor
You need to assign some signals to global networks. I don't know CII well but I know that later families can't feed all the clock signals in a LAB from local routing; some of them have to come from global routing as well. Use the assignment editor to make the assignments, or google "Quartus assign global" to find examples of how it's done.
Cheers, Adrian - Altera_Forum
Honored Contributor
--- Quote Start --- You need to assign some signals to global networks. I don't know CII well but I know that later families can't feed all the clock signals in a LAB from local routing; some of them have to come from global routing as well. Use the assignment editor to make the assignments, or google "Quartus assign global" to find examples of how it's done. Cheers, Adrian --- Quote End --- Thanks for your suggestion Adrian, how about Cyclone II clock, is it from crystal or from PLL, I'm abit confuse... thanks - Altera_Forum
Honored Contributor
I don't believe any of our devices have on-board crystals (disclaimer: I'm a software guy, not hardware) so you have to generate the signals off-chip and feed them into the device through a pin. At that point you can use the clock directly, or use it to drive a PLL and use the PLL-generated clock. Check out http://www.altera.com/literature/lit-cyc2.jsp for more details on the hardware; to instantiate a PLL using Quartus, see http://www.altera.com/literature/ug/ug_altpll.pdf.