Altera Corporation 10–23
July 2005 Stratix Device Handbook, Volume 2
Transitioning APEX Designs to Stratix & Stratix GX Devices
device with the altclklock megafunction, there are specific cases
where you must use the altpll megafunction, as explained in this
section.
In the MegaWizard Plug-In Manager, select the altpll megafunction in
the I/O directory from the Available Megafunctions box (see
Figure 10–9). The altclklock megafunction is also available from the
Quartus II software for backward compatibility, but instantiates the new
altpll megafunction when targeting Stratix or Stratix GX devices. The
Quartus II Compiler automatically selects whether the altpll module
uses either an enhanced PLL or a fast PLL based on the design’s PLL
needs and the feature requirements of each PLL.
Figure 10–9. altpll Megafunction Selection in the MegaWizard Plug-In
Manager
You can compile APEX II, APEX 20KE, and APEX 20KC designs using the
altclklock megafunction in normal mode for Stratix and Stratix GX
devices without updating the megafunction. However, you should
replace the altclklock megafunction with the altpll megafunction.
If the Quartus II software cannot implement the requested clock
multiplication and division of the PLL, the compiler reports an error
message with the appropriate reason stated.
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