Specifications

Figure 3-3: Input Register of a Variable Precision DSP Block in 27 x 27 Mode for Cyclone V Devices
The figures show the data registers only. Registers for the control signals are not shown.
dataa_y0[26..0]
dataa_z0[25..0]
dataa_x0[26..0]
scanin[26..0]
CLK[2..0]
ENA[2..0]
ACLR[0]
scanout[26..0]
Pre-Adder
Cyclone V Devices
Each variable precision DSP block has two 19-bit pre-adders. You can configure these pre-adders in the
following configurations:
• Two independent 19-bit pre-adders
• One 27-bit pre-adder
The pre-adder supports both addition and subtraction in the following input configurations:
• 18-bit (signed) addition or subtraction for 18 x 19 mode
• 17-bit (unsigned) addition or subtraction for 18 x 19 mode
• 26-bit addition or subtraction for 27 x 27 mode
Internal Coefficient
The Cyclone V variable precision DSP block has the flexibility of selecting the multiplicand from either the
dynamic input or the internal coefficient.
The internal coefficient can support up to eight constant coefficients for the multiplicands in 18-bit and
27-bit modes. When you enable the internal coefficient feature, COEFSELA/COEFSELB are used to control
the selection of the coefficient multiplexer.
Multipliers
A single variable precision DSP block can perform many multiplications in parallel, depending on the data
width of the multiplier.
Variable Precision DSP Blocks in Cyclone V Devices
Altera Corporation
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CV-52003
Pre-Adder
3-8
2013.05.06