DSP Builder for Intel® FPGAs (Advanced Blockset): Handbook

ID 683337
Date 5/27/2022

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15.4.52. Select

The Select block outputs one of the data signals (a, b, ...) if its paired select input (0, 1, ...) has a non-zero value.

q = 0 ? a : (1 ? b : d)

If all select inputs are 0, the Select block outputs the default value d. At most one select input should be high at a time.

Table 242.  Parameters for the Select Block
Parameter Description
Output data type mode Determines how the block sets its output data type:
  • Inherit via internal rule: the number of integer and fractional bits is the maximum of the number of bits in the input data types.
  • Specify via dialog: you can set the output type of the block explicitly using additional fields that are available when this option is selected.This option reinterprets the output bit pattern from the LSB up according to the specified type.
  • Boolean: the output type is Boolean.
Output data type Specifies the output data type. For example, sfix(16), uint(8).
Output scaling value Specifies the output scaling value. For example, 2^-15.
Number of cases Specifies the number of non-default data inputs.
Table 243.  Port Interface for the Select Block
Signal Direction Type Description Vector Data Support Complex Data Support
d Input Any fixed- or floating-point type Default input Yes Yes
0, 1, 2, ... Input Boolean One-hot select inputs Yes No
a, b, c, ... Input Any fixed- or floating-point type Data input Yes Yes
q Output Derived fixed- or floating-point type Result Yes Yes