EP2S130F1020I4 Datasheet, PDF (533/768 Pages) List of Unclassifed Manufacturers – Stratix II Device Handbook, Volume 1

DSP Blocks in Stratix II and Stratix II GX Devices
Figure 6–7. Adder/Output Block Architecture
adder1_round (2)
Result A /
accum_sload_upper_data
accum_sload0 (2)
Note (1)
Accumulator Feedback
Output Select
Multiplexer
Output Registers
addnsub1 (2)
Result B
Adder/
Subtractor/
Accumulator 1
Q1.15
Rounding
(3)
signa (2)
overflow0
signb (2)
Result C /
accum_sload_upper_data
accum_sload1 (2)
addnsub3 (2)
Result D
adder3_round (2)
Summation
Adder/
Subtractor/
Accumulator 2
Q1.15
Rounding
(3)
Accumulator Feedback
Output
Register Block
overflow1
Notes to Figure 6–7:
(1) The adder/output block is in 18 × 18 mode. In 9 × 9 mode, there are four adder/subtractor blocks and two
summation blocks.
(2) You can send these signals through a pipeline register. The pipeline length can be set to 1 or 2.
(3) Q1.15 inputs are not available in 9 × 9 or 36 × 36 modes.
Adder/Subtractor/Accumulator Block
The adder/subtractor/accumulator block is the first level adder stage of
the adder/output block. This block can be configured as an accumulator
or as an adder/subtractor.
Altera Corporation
January 2008
6–17
Stratix II Device Handbook, Volume 2