ID:14887 Can't pack register into I/O input cell <name> -- the I/O input buffer fans out to multiple nodes, but the fanout must be to exactly one register node.

CAUSE: You turned on the Fast Input Register logic option for the specified register. The specified node can also be a PLL compensated pin in source synchronous mode. However, the register has no valid packable connection from its input port to an I/O pin. The Fitter cannot honor the assignment because the I/O buffer associated with the I/O fans out to multiple destinations. For a register to be packed into an input I/O cell, the I/O input buffer must only drive the DATA_D port of the register, and no additional fanouts.

ACTION: Remove the Fast Input Register logic option assignment on the register or modify the design so that the I/O input buffer only drives one destination register.