Quartus II Settings File Reference Manual - Altera

6–24 Chapter 6: Fitter Assignments
AUTO_PACKED_REGISTERS_STRATIXII
AUTO_PACKED_REGISTERS_STRATIXII
Type
Allows the Compiler to combine a register and a combinational function, or to
implement registers using I/O cells, RAM blocks, or DSP blocks instead of logic cells.
This option controls how aggressively the Fitter combines registers with other
function blocks to reduce the area of the design. Generally, the Auto or Sparse Auto
settings should be used for this option. The other options limit the flexibility of the
Fitter to combine registers with other function blocks and can result in no fits. When
Auto, the default setting is selected, the Fitter attempts to achieve the best
performance with good area. If necessary, additional logic is combined to reduce the
area of the design so that it can fit within the selected device. When this setting is
Sparse Auto, the Fitter attempts to achieve the highest performance with possibly
increased area, but without exceeding the logic capacity of the device. If this option is
set to Off, the Fitter does not combine registers with other functions. The Off setting
severely increases the area of the design and may cause a no fit. If this option is set to
Sparse, the Fitter combines functions in a way which improves performance for many
designs. If this option is set to Normal, the Fitter combines functions that are expected
to maximize design performance and reduce area. When this option is set to
Minimize Area, the Fitter aggressively combines unrelated functions to reduce the
area required for placing the design, at the expense of performance. When this option
is set to Minimize Area with Chains, the Fitter even more aggressively combines
functions that are part of register cascade chains or can be converted to register
cascade chains. If this option is set to any value but Off, registers are combined with
I/O cells to improve I/O timing (as long as the Optimize IOC Register Placement
For Timing option allows it), and with DSP blocks and RAM blocks to reduce the area
required for placing the design or to improve timing when possible.
Enumeration
■ Auto
■ Minimize Area
■ Minimize Area with Chains
■ Normal
■ Off
■ Sparse
■ Sparse Auto
Device Support
This setting can be used in projects targeting the following device families:
■ Arria GX
■ Arria II GX
■ Arria II GZ
■ Arria V
■ Cyclone II
Quartus Settings File June 2012 Altera Corporation
Reference Manual