
6–6
Altera Corporation
Stratix II Device Handbook, Volume 2
January 2008
DSP Block Overview
Figure 6–2 shows the DSP block configured for 18 × 18 multiplier mode.
Figure 6–3 shows the 9 × 9 multiplier configuration of the DSP block.
Figure 6–2. DSP Block in 18 × 18 Mode
Adder/
Subtractor/
Accumulator
1
Adder
Multiplier Block
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
PRN
CLRN
DQ
ENA
Summation
Block
Adder Output Block
Adder/
Subtractor/
Accumulator
2
Q1.15
Round/
Saturate
Q1.15
Round/
Saturate
Q1.15
Round/
Saturate
Q1.15
Round/
Saturate
to MultiTrack
Interconnect
CLRN
DQ
ENA
From the row
interface block
Optional Serial Shift
Register Inputs from
Previous DSP Block
Optional Serial Shift
Register Outputs to
Next DSP Block
in the Column
Optional Input Register
Stage with Parallel Input or
Shift Register Configuration
Optional Pipline
Register Stage
Summation Stage
for Adding Four
Multipliers Together
Optional Stage Configurable
as Accumulator or Dynamic
Adder/Subtractor
Output
Selection
Multiplexer
Q1.15
Round/
Saturate
Q1.15
Round/
Saturate