Stratix® 10 Variable Precision DSP Blocks User Guide

ID 683832
Date 7/08/2024
Public
Document Table of Contents

7.3.5. Accumulator Tab

Table 40.  Accumulator Tab
Parameter Value Default Value Description
Enable accumulator?

YES,

NO

NO Select YES to enable the accumulator.

You must select Register output of adder unit when using accumulator feature.

What is the accumulator operation type?

ADD,

SUB

ADD Specifies the operation of the accumulator:
  • ADD for addition operation
  • SUB for subtraction operation.

You must select YES for Enable accumulator? parameter to enable this option.

Preload Constant
Enable preload constant

On

Off

Off Enable the accum_sload or sload_accum signals and the registers input to dynamically select the input to the accumulator.

When accum_sload is low or sload_accum is high, the multiplier output is feed into the accumulator.

When accum_sload is high or sload_accum is low, a user specified preload constant is feed into the accumulator.

You must select YES for Enable accumulator parameter to enable this option.

What is the input of accumulate port connected to?

ACCUM_SLOAD,

SLOAD_ACCUM

ACCUM_SLOAD Specifies the behavior of accum_sload/sload_accum signal.

ACCUM_SLOAD: Drive accum_sload low to load the multiplier output to the accumulator.

SLOAD_ACCUM: Drive sload_accum high to load the multiplier output to the accumulator.

You must select Enable preload constant option to enable this parameter.

Select value for preload constant 0 - 64 64 Specify the preset constant value.

This value can be 2N where N is the preset constant value.

N=64 represents a constant zero.

You must select Enable preload constant option to enable this parameter.

What is the source for clock input?

Clock0

Clock1

Clock2

Clock0 Select Clock0 , Clock1 or Clock2 to specify the input clock signal for accum_sload/sload_accum register.

You must select Enable preload constant option to enable this parameter.

What is the source for asynchronous clear input?

NONE

ACLR0

ACLR1

NONE Specifies the asynchronous clear source for the accum_sload/sload_accum register.

You must select Enable preload constant option to enable this parameter.

What is the source for synchronous clear input?

NONE

SCLR0

SCLR1

NONE Specifies the synchronous clear source for the accum_sload/sload_accum register.

You must select Enable preload constant option to enable this parameter.

Enable double accumulator

TRUE

FALSE

FALSE To enable or disable the double accumulator feature.