EP2AGX95EF29C6N Datasheet, PDF (106/380 Pages) Altera Corporation – Device Interfaces and Integration

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Chapter 4: DSP Blocks in Arria II Devices
Arria II Operational Mode Descriptions
If both the rounding and saturation logic units are used for an accumulation type of
operation, the format is:
Result = SAT[RND[∑(A × B)]]
DSP Block Control Signals
You can configure the Arria II DSP block with a set of static and dynamic signals. At
run time, you can configure the DSP block dynamic signals to toggle or not.
Table 4–9 shows a list of dynamic signals for the DSP block. Table 4–9 lists the DSP
block dynamic signals.
Table 4–9. DSP Block Dynamic Signals for DSP Block in Arria II Devices (Part 1 of 2)
Signal Name
Function
DSP Block Dynamic Signals per Half-DSP Block
Signed/unsigned control for all multipliers and adders.
signa for “multiplicand” input bus to dataa[17:0] each multiplier.
signa
signb
signb for “multiplier” input bus datab[17:0] to each multiplier.
■ signa = 1, signb = 1 for signed-signed multiplication
■ signa = 1, signb = 0 for signed-unsigned multiplication
■ signa = 0, signb = 1 for unsigned-signed multiplication
■ signa = 0, signb = 0 for unsigned-unsigned multiplication
Round control for first stage round/saturation block.
output_round
■ output_round = 1 for rounding on multiply output
■ output_round = 0 for normal multiply output
Round control for second stage round/saturation block.
chainout_round
■ chainout_round = 1 for rounding on multiply output
■ chainout_round = 0 for normal multiply output
output_saturate
Saturation control for first stage round/saturation block for Q-format
multiply. If both rounding and saturation is enabled, saturation is done
on the rounded result.
■ output_saturate = 1 for saturation support
■ output_saturate = 0 for no saturation support
chainout_saturate
Saturation control for second stage round/saturation block for
Q-format multiply. If both rounding and saturation is enabled,
saturation is done on the rounded result.
■ chainout_saturate = 1 for saturation support
■ chainout_saturate = 0 for no saturation support
Dynamically specifies whether the accumulator value is zero.
accum_sload
■ accum_sload = 0, accumulation input is from the output registers
■ accum_sload = 1, accumulation input is set to be zero
zero_chainout
Dynamically specifies whether the chainout value is zero.
zero_loopback
Dynamically specifies whether the loopback value is zero.
rotate
rotation = 1, rotation feature is enabled
Count
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1
1
1
1
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1
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Arria II Device Handbook Volume 1: Device Interfaces and Integration
December 2010 Altera Corporation