Altera Quartus II Settings File - Manual (Page 707)

QII_AUTO_PACKED_REGISTERS
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.
Old Name
AUTO_PACKED_REGISTERS_ARMSTRONG, AUTO_PACKED_REGISTERS_STRATIXII, Auto
Packed Registers -- Stratix II/II GX/III Cyclone II/III Arria GX
Type
Enumeration
Values
• Auto
• Minimize Area
• Minimize Area with Chains
• Normal
• Off
• Sparse
• Sparse Auto
Device Support
This setting can be used in projects targeting any Altera device family.
Notes
This assignment supports Fitter wildcards.
This assignment is included in the Fitter report.
MNL-Q21005
2015.05.04
QII_AUTO_PACKED_REGISTERS 707
Quartus Settings File Reference Manual Altera Corporation
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