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Honored Contributorbuffer for clock signal?
Do Quartus has an buffer for split the clock signal (200MHz)?
----------------------------- clock (200MHz) | | | | | | | | | node1 node2 node3Forum Discussion
11 Replies
Altera_Forum--- Quote Start --- Do Quartus has an buffer for split the clock signal (200MHz)? ----------------------------- clock (200MHz) | | | | | | | | | node1 node2 node3 --- Quote End --- Hi, in case your are using a global input, the clock is distributed to all parts the FPGA. Kind regards GPK- Altera_Forum
Hi!
no, the 200 MHz clock is the out of pll, it is internally of fpga. ------200MHz------ AND PORT------------ . ..............................................| | . ..............................................| | . ..............................................| | . ............................................nodes - Altera_Forum--- Quote Start --- Hi! no, the 200 MHz clock is the out of pll, it is internally of fpga. ------200MHz------ AND PORT------------ . ..............................................| | . ..............................................| | . ..............................................| | . ............................................nodes --- Quote End --- Hi, why do you want to place a buffer at that point ? Kind regards GPK
- Altera_Forum
because the quartus do:
what is "ripple clock"? Warning: Found 3 node(s) in clock paths which may be acting as ripple and/or gated clocks -- node(s) analyzed as buffer(s) resulting in clock skew Info: Detected ripple clock "inst5" as buffer Info: Detected ripple clock "myflipflop:inst14|Q" as buffer Info: Detected gated clock "inst18" as buffer - Altera_Forum--- Quote Start --- because the quartus do: what is "ripple clock"? Warning: Found 3 node(s) in clock paths which may be acting as ripple and/or gated clocks -- node(s) analyzed as buffer(s) resulting in clock skew Info: Detected ripple clock "inst5" as buffer Info: Detected ripple clock "myflipflop:inst14|Q" as buffer Info: Detected gated clock "inst18" as buffer --- Quote End --- Hi, I think the Info is a little bit misleading. It only means that Quartus found 3 nodes which drives the clock inputs of e.g. registers. You don't need to do any buffering here, but this kind of clock generation could cause a lot of timing violations. Kind regards GPK
- Altera_Forum--- Quote Start --- Hi, I think the Info is a little bit misleading. It only means that Quartus found 3 nodes which drives the clock inputs of e.g. registers. You don't need to do any buffering here, but this kind of clock generation could cause a lot of timing violations. Kind regards GPK --- Quote End --- Hi, You should find a lot of info's under: http://www.alteraforum.com/forum/showthread.php?t=2250. Kind regards GPK
- Altera_Forum--- Quote Start --- Hi, You should find a lot of info's under: http://www.alteraforum.com/forum/showthread.php?t=2250. Kind regards GPK --- Quote End --- Hi, I found an other thread for you: http://www.alteraforum.com/forum/showthread.php?t=2388. Kind regards GPK
- Altera_Forum
ok! tnx! very good doc!
- Altera_Forum
from doc:
"The preferred method of creating enabled clocks is to use the ALTCLKCTRL MegaFunction." has quartusII(web ed) this megafunction? regards - Altera_Forum--- Quote Start --- from doc: "The preferred method of creating enabled clocks is to use the ALTCLKCTRL MegaFunction." has quartusII(web ed) this megafunction? regards --- Quote End --- Hi, yes. Start the megawizard ( tools -> Megawizard Plug-in manager -> next -> I/O -> ALTCLKCTRL) Kind regards GPK
