一、AMBA总线协议模型架构

核心模块组成

二、AHB总线Verilog实现

2.1 模块接口定义

module ahb_master #(
    parameter ADDR_WIDTH = 32,
    parameter DATA_WIDTH = 32
)(
    input wire HCLK,
    input wire HRESETn,
    output reg [ADDR_WIDTH-1:0] HADDR,
    output reg [DATA_WIDTH-1:0] HWDATA,
    input wire [DATA_WIDTH-1:0] HRDATA,
    output reg HWRITE,
    output reg [1:0] HTRANS,
    input wire HREADY,
    output reg [2:0] HBURST
);
    // 状态机定义
    typedef enum logic [2:0] {
        IDLE,
        BUSY,
        NONSEQ,
        SEQ,
        RETRY
    } ahb_state_t;
    
    ahb_state_t current_state, next_state;
    
    // 传输控制逻辑
    always_ff @(posedge HCLK or negedge HRESETn) begin
        if (!HRESETn) current_state <= IDLE;
        else current_state <= next_state;
    end
    
    // 状态转移逻辑
    always_comb begin
        case(current_state)
            IDLE: next_state = (HTRANS != IDLE) ? NONSEQ : IDLE;
            NONSEQ: next_state = (HREADY) ? SEQ : NONSEQ;
            SEQ: next_state = (HREADY) ? SEQ : NONSEQ;
            RETRY: next_state = (HREADY) ? IDLE : RETRY;
            default: next_state = IDLE;
        endcase
    end
endmodule

2.2 关键实现技术

1. 突发传输控制：通过HBURST信号生成连续地址

   always_ff @(posedge HCLK) begin
       if (HTRANS == NONSEQ) begin
           HADDR <= target_addr;
       end else if (HTRANS == SEQ) begin
           HADDR <= HADDR + (1 << AWIDTH);
       end
   end
   

2. 仲裁逻辑：多主设备竞争总线控制权

   assign HGRANT = (arb_priority == MASTER_ID) ? 1 : 0;
   

三、AXI总线Verilog实现

3.1 通道信号定义

// 写地址通道
output reg [31:0] AWADDR;
output reg [7:0]  AWLEN;
output reg [2:0]  AWSIZE;
output reg        AWVALID;

// 写数据通道
output reg [31:0] WDATA;
output reg [3:0]  WSTRB;
output reg        WVALID;

// 写响应通道
input  wire [1:0] BRESP;
input  wire       BVALID;

// 读地址通道
output reg [31:0] ARADDR;
output reg [7:0]  ARLEN;
output reg [2:0]  ARSIZE;
output reg        ARVALID;

// 读数据通道
input  wire [31:0] RDATA;
input  wire [1:0] RRESP;
input  wire       RVALID;

3.2 状态机实现

typedef enum logic [3:0] {
    IDLE,
    WRITE_ADDR,
    WRITE_DATA,
    WRITE_RESP,
    READ_ADDR,
    READ_DATA,
    DONE
} axi_state_t;

axi_state_t state, next_state;

always_ff @(posedge ACLK or negedge ARESETn) begin
    if (!ARESETn) state <= IDLE;
    else state <= next_state;
end

always_comb begin
    case(state)
        IDLE: next_state = (aw_valid) ? WRITE_ADDR : IDLE;
        WRITE_ADDR: next_state = (aw_ready) ? WRITE_DATA : WRITE_ADDR;
        WRITE_DATA: next_state = (w_valid) ? WRITE_DATA : WRITE_RESP;
        WRITE_RESP: next_state = (b_valid) ? DONE : WRITE_RESP;
        // 其他状态转换逻辑...
    endcase
end

四、APB总线Verilog实现

4.1 主设备核心逻辑

module apb_master #(
    parameter ADDR_WIDTH = 32,
    parameter DATA_WIDTH = 32
)(
    input wire PCLK,
    input wire PRESETn,
    output reg PSEL,
    output reg PENABLE,
    output reg PWRITE,
    output reg [ADDR_WIDTH-1:0] PADDR,
    output reg [DATA_WIDTH-1:0] PWDATA,
    input wire [DATA_WIDTH-1:0] PRDATA,
    input wire PREADY,
    input wire PSLVERR
);

    typedef enum logic [1:0] {
        IDLE,
        SETUP,
        ACCESS
    } apb_state_t;

    apb_state_t state, next_state;

    always_ff @(posedge PCLK or negedge PRESETn) begin
        if (!PRESETn) state <= IDLE;
        else state <= next_state;
    end

    always_comb begin
        case(state)
            IDLE: begin
                if (transfer_pending) next_state = SETUP;
                else next_state = IDLE;
            end
            SETUP: next_state = ACCESS;
            ACCESS: begin
                if (PREADY) next_state = IDLE;
                else next_state = ACCESS;
            end
        endcase
    end

    always_ff @(posedge PCLK) begin
        case(state)
            SETUP: begin
                PSEL <= 1;
                PADDR <= target_addr;
                PWRITE <= write_en;
                PWDATA <= write_data;
            end
            ACCESS: begin
                PENABLE <= 1;
            end
        endcase
    end
endmodule

五、验证与调试技术

5.1 测试平台设计

module tb_ahb_master();
    reg HCLK = 0;
    reg HRESETn = 0;
    wire [31:0] HADDR;
    wire [31:0] HWDATA;
    reg [31:0] HRDATA;
    reg HWRITE;
    reg [1:0] HTRANS;
    wire HREADY;
    reg [2:0] HBURST;

    ahb_master uut (
        .HCLK(HCLK),
        .HRESETn(HRESETn),
        .HADDR(HADDR),
        .HWDATA(HWDATA),
        .HRDATA(HRDATA),
        .HWRITE(HWRITE),
        .HTRANS(HTRANS),
        .HREADY(HREADY),
        .HBURST(HBURST)
    );

    initial begin
        HRESETn = 0; #10;
        HRESETn = 1;
        HTRANS = 2'b01; // NONSEQ
        HADDR = 32'h1000;
        HWDATA = 32'hDEADBEEF;
        HWRITE = 1;
        #20;
        HTRANS = 2'b00; // IDLE
        #100;
        $finish;
    end

    always #5 HCLK = ~HCLK;
endmodule

5.2 性能验证方法

1. 时序分析：使用静态时序分析工具验证关键路径

   report_timing -delay_type max -sort_by group
   

2. 功耗分析：通过仿真获取动态/静态功耗数据

   initial begin
       $display("Dynamic Power: %.2f mW", power_dynamic);
       $display("Leakage Power: %.2f mW", power_leakage);
   end
   

参考代码 AMBA总线的Verilog语言模型 www.youwenfan.com/contentcsh/56343.html

通过上述模型实现，开发者可构建符合AMBA标准的总线系统。建议结合具体应用场景选择协议类型，并通过仿真验证确保时序正确性和功能完整性。