Forum Discussion
Honored ContributorALTMEMPHY without PLL
I created a DDR2 controller with Megawizard. My question is there a way to create it without PLL. I want to use a own PLL, since our design uses all PLL, and we would like to reuse one of the existing PLL to generate the clocks, but I havn't found a setting in the MegaWizard to do that.
We're using Cyclone III.2 Replies
Altera_ForumI've checked the design, it doesn't seem possible to reuse any output.
I thought it might be possble, since I used a Xilinx controller before and this one only used two clocks. The Cyclone3 controller needs the 5 output of the PLL.- Altera_Forum
The PLL is integral to operation. DDR2 is all about passing data between phase-shifted clock domains and what-not. Maybe you can create the clocks you need from the DDR2 PLL? You can go into the PLL inside the DDR2 and modify it, such as adding another output. (The Cyclone III PLLs don't have a ton of outputs, so I'm not sure what's possible. I've done this on Stratix DDR2 designs before.)
