4777 - iCEcube2: Placer error saying the PLL instance cannot be placed.
4777 - iCEcube2: Placer error saying the PLL instance cannot be placed.
Description:
When using PLL in iCEcube2, an error may occur saying it cannot be placed.
Solution:
The issue is probably due to the "
PLL Placement Rules
" getting violated.
The PLL placement rules are specified in the
iCE40 sysCLOCK PLL Design and User Guide
Technical Note
under "Hardware Design Considerations".
Modifying the user design accordingly will help to resolve this issue.