Asynchronous FIFO Verilog Easy Explanation

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Күн бұрын

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@shreyasgaiki1314 28 күн бұрын

Hi semidesign, It is usually not a good idea to drive the full and empty output logic combinationally and assigned to the final output. When there is a push and the current wptr is MAX-1, then it will go to MAX value. You can check this condition and pass it through a flop. The output of the flop is full. Same for empty. This way the final full and empty signals come from flops which greatly reduces output delay.

@BITSIAN23 4 ай бұрын

Here is the complete code - " `timescale 1ns / 1ps ////////////////////////////////////////////////////////////////////////////////// // // Create Date: 19.08.2024 23:34:43 // Design Name: Asynchronous FIFO // Module Name: top // Project Name: // Target Devices: // Tool Versions: // Description: // This module implements an Asynchronous FIFO with separate read and write clocks. // It includes logic to handle data synchronization across different clock domains // using Gray code pointers to avoid metastability and synchronization errors. // // Dependencies: None // // Revision: // Revision 0.01 - File Created // Additional Comments: // ////////////////////////////////////////////////////////////////////////////////// module top ( input wr_clk, // Write clock input rd_clk, // Read clock input rst, // Asynchronous reset input wr_en, // Write enable signal input rd_en, // Read enable signal input [7:0] write_data, // Data input for writing to FIFO output reg [7:0] read_data, // Data output for reading from FIFO output wire empty, // Flag to indicate FIFO is empty output wire full // Flag to indicate FIFO is full ); parameter fifo_depth = 8; // FIFO depth is 8, so address pointer will be 3 bits wide parameter add_size = 4; // Address size set to 4 bits to handle full/empty condition // Define the read and write pointers with 4 bits each reg [3:0] wptr, rptr; wire [3:0] wptr_gray, rptr_gray; // FIFO buffer memory of 8 entries, each 8 bits wide reg [7:0] mem [7:0]; // Synchronized write and read pointers (Gray code) reg [3:0] wptr_gray_sync; reg [3:0] wptr_gray_ff1, wptr_gray_ff2; reg [3:0] rptr_gray_sync; reg [3:0] rptr_gray_ff1, rptr_gray_ff2; // Write data into FIFO buffer // This block is triggered by the write clock and checks for write enable and FIFO full conditions always @(posedge wr_clk) begin if (rst) begin // Reset write pointer to zero wptr > 1); // Synchronize the write pointer to the read clock domain // This prevents metastability when comparing pointers across different clock domains always @(posedge rd_clk) begin if (rst) begin // Reset synchronization flip-flops wptr_gray_ff1

@SrividyaKummari 2 ай бұрын

need testbench

@shreyasgaiki1314 28 күн бұрын

Here the full condition logic does not match with the one in the video. It should be - wptr_gray[2] != rptr_gray_sync[2] . Above they are checking for equal which is done for binary comparison not gray.