Accumulator Module

Description

The Accumulator module (hs_npu_accumulator) performs an accumulation operation, adding a bias to each input data value and outputting the result. It accepts a bias value and enables accumulation based on a valid input signal. The accumulated result is output along with a signal indicating validity.

The OUTPUT_DATA_WIDTH parameter defines the width of the input and output data, allowing flexibility for various data formats.

I/O Table

Input Table

Input Name	Direction	Type	Description
`clk`	Input	`logic`	Clock signal for synchronization.
`rst_n`	Input	`logic`	Reset signal (active low) to initialize the module.
`input_data`	Input	`logic[OUTPUT_DATA_WIDTH-1:0]`	Data to be accumulated with the bias value.
`valid_i`	Input	`logic`	Valid signal indicating `input_data` is ready.
`bias_in`	Input	`logic[OUTPUT_DATA_WIDTH-1:0]`	Bias value to add to `input_data`.
`bias_en`	Input	`logic`	Enable signal for updating the stored bias.

Output Table

Output Name	Direction	Type	Description
`result`	Output	`logic[OUTPUT_DATA_WIDTH-1:0]`	Accumulated result after adding `input_data` and the stored bias.
`valid_o`	Output	`logic`	Signal indicating the result is valid.

Module Behavior and Data Flow

Bias Handling: The accumulator holds a bias value, which can be updated whenever the bias_en signal is asserted. When bias_en is active, the bias is set to the value on bias_in; otherwise, it retains its previous value.
Accumulation Process: When valid_i is asserted, the module adds the stored bias to the incoming input_data and outputs the result through result, with valid_o set high to indicate a valid output. If valid_i is deasserted, result outputs zero and valid_o is low, indicating no valid accumulation result.

Diagram

The diagram is trivial.

The bias value is floped, only registered when bias_en is set.

When valid_i is set:

    result  = input_data + bias;
    valid_o = 1;

Else:

    result  = 0;
    valid_o = 0;

File Name	Type
hs_npu_accumulator	Top Module