4–4
Chapter 4: DSP Blocks in Arria II Devices
Simplified DSP Operation
Arria II Device Handbook Volume 1: Device Interfaces and Integration
December 2010
Altera Corporation
Simplified DSP Operation
In Arria II devices, the fundamental building block is a pair of 18 × 18-bit multipliers
followed by a first-stage 37-bit addition and subtraction unit shown in
. For all signed numbers, input and output data is represented in
2’s-complement format only.
The structure shown in
is useful for building more complex structures,
such as complex multipliers and 36 × 36 multipliers, as described in later sections.
Each Arria II DSP block contains four two-multiplier adder units
(2 two-multiplier adder units per half block). Therefore, there are eight 18 × 18
multiplier functionalities per DSP block. For a detailed diagram of the DSP block,
refer to
.
Following the two-multiplier adder units are the pipeline registers, the second-stage
adders, and an output register stage. You can configure the second-stage adders to
provide the alternative functions shown in
and
per half
block.
Equation 4–1. Multiplier Equation
P[36..0] = A
0
[17..0] × B
0
[17..0] ± A
1
[17..0] × B
1
[17..0]
Figure 4–2. Basic Two-Multiplier Adder Building Block
D
Q
D
Q
A0[17..0]
A1[17..0]
B1[17..0]
B0[17..0]
P[36..0]
+/-
Equation 4–2. Four-Multiplier Adder Equation
Z[37..0] = P
0
[36..0] + P
1
[36..0]