New Contributor
ContributorHi there, have you tried logic lock to constrain the two registers to the same ALM. You can get reference from the following link: https://www.intel.com/content/www/us/en/docs/programmable/683230/18-1/creating-regions-with-the-chip-planner.html
New ContributorLogic lock didn't help because Quartus thought it needed a larger area to locate the circuit. However, I somehow managed the implementation: instead of DFF primitives, I described the register using a process and manually deployed the elements in Chip Planner. After saving the placement and recompiling, the ALM configuration was as expected. The problem of implementing additional ALMs to set a fixed value of '1...1' on one of the inputs remained, but I can live with that.
