Honored Contributor
Honored ContributorA few capacitors will probably not be enough.
Altera recommends a capacitor for each power pin end especial care for PLL power supply. We had a lot of problems with improper power decoupling on Cyclone II chips in TQFP package. Check decoupling instructions in the high speed design document for Stratix chips. On our first design the processor crashed while accessing to the external SRAM, bot worked correctly from the internal memory, the problem was ground bouncing due to toggling output signals. This problem can be alleviated by lowering the current strength of Cyclone output pins. After we improved the decoupling we got crashes due to some signals disturbing a PLL. So we are creating a third redesign. IzI
