how many ddr2 controller can be used in a cyclone 4 device?

[Altera_Forum]

hi everyone, 

 who can tell me how many ddr2 controller can be used in a cyclone 4 device?  thank you!

[Altera_Forum]

It can be a complicated answer for such a general question... 

To make it simple, you can have one controller for each general purpose PLL you have in your device as each controller will use one general purpose PLL and PLLs can't be shared between controllers.

[Altera_Forum]

Can you share a PLL with two DDR2 controllers if you run the two DDR2 banks with the same clock?

[Altera_Forum]

--- Quote Start ---  Can you share a PLL with two DDR2 controllers if you run the two DDR2 banks with the same clock?  --- Quote End ---     It was possible with the legacy controller. But this is not the case with the ALTMEMPHY controller. It is not possible to use the legacy controller on Cyclone IV devices

[Altera_Forum]

While you can't share the complete pll, I know in cyclone III you can share some of the clocks if they operate at the same frequency. Thus, if your limitation is global clock usage you can shrink that down. Saves an extra 2 global clocks for each controller you add.