EP2AGX95EF29C6N Datasheet, PDF (83/380 Pages) Altera Corporation – Device Interfaces and Integration

Chapter 4: DSP Blocks in Arria II Devices
4–7
Operational Modes Overview
Operational Modes Overview
You can use each Arria II DSP block in one of six basic operational modes. Table 4–2
lists the six basic operational modes and the number of multipliers that you can
implement in a single DSP block.
Table 4–2. DSP Block Operational Modes for Arria II Devices
Mode
Multiplier Number of # per Signed or RND, In Shift Chainout 1st Stage 2nd Stage
in Width Multiplier Block Unsigned SAT Register Adder Add/Sub Add/Acc
9 bits
1
8
Both
No
No
No
—
—
12 bits
1
Independent
Multiplier
18 bits
1
36 bits
1
6
Both
No
No
No
—
—
4
Both
Yes
Yes
No
—
—
2
Both
No
No
No
—
—
Double
1
2
Both
No
No
No
—
—
Two-Multiplier
Adder (1)
18 bits
2
4 Signed (2) Yes
No
No
Both
—
Four-Multiplier
Adder
18 bits
4
2
Both
Yes
Yes
Yes
Both Add Only
Multiply
Accumulate
18 bits
4
2
Both
Yes
Yes
Yes
Both
Both
Shift (3) 36 bits (4)
1
2
Both
No
No
—
—
—
High Precision
Multiplier Adder
18  36
2
2
Both
No
No
No
—
Add Only
Notes to Table 4–2:
(1) This mode also supports loopback mode. In loopback mode, the number of loopback multipliers per DSP block is two. You can use the remaining
multipliers in regular two-multiplier adder mode.
(2) Unsigned value is also supported, but you must ensure that the result can be contained in 36 bits.
(3) Dynamic shift mode supports arithmetic shift left, arithmetic shift right, logical shift left, logical shift right, and rotation operation.
(4) Dynamic shift mode operates on a 32-bit input vector, but the multiplier width is configured as 36 bits.
The DSP block consists of two identical halves (top-half and bottom-half). Each half
has four 18 × 18 multipliers.
The Quartus^® II software includes megafunctions that control the mode of operation
of the multipliers. After making the appropriate parameter settings with the
megafunction’s MegaWizard^ Plug-In Manager, the Quartus II software
automatically configures the DSP block.
Arria II DSP blocks can operate in different modes simultaneously. Each half block is
fully independent except for the sharing of the clock, ena, and the aclr signals. For
example, you can break down a single DSP block to operate a 9 × 9 multiplier in one
half block and an 18 × 18 two-multiplier adder in the other half block. This increases
DSP block resource efficiency and allows you to implement more multipliers in an
Arria II device. The Quartus II software automatically places multipliers that can
share the same DSP block resources in the same block.
December 2010 Altera Corporation
Arria II Device Handbook Volume 1: Device Interfaces and Integration