uart中的FIFO模块

UART中的FIFO模块是一种先进先出的缓存，用于存储串口接收和发送的数据。它可以有效地减少CPU的负担，提高系统性能。

UART的接收FIFO模块可以存储多个字节的数据，当数据到达时，它将被存储在FIFO中，而不是立即传输给CPU。当CPU准备好处理数据时，它可以从FIFO中读取数据。如果FIFO已满，则新到达的数据将被丢弃。

UART的发送FIFO模块也可以存储多个字节的数据，当CPU准备好发送数据时，它将把数据写入FIFO中。UART发送器将从FIFO中读取数据并将其发送到串口线路上。如果FIFO已满，则新写入的数据将被丢弃。

FIFO的大小可以根据应用程序的需求进行配置。较大的FIFO可以提高系统性能，但也会增加系统的硬件成本。

相关问题

uart带fifo，接收模块，发送模块，控制模块的verilog代码及其测试代码

以下是一个带有FIFO的UART接收器和发送器以及控制模块的Verilog代码及其测试代码：

module uart(
  input clk,
  input reset,

  // 发送端口
  output tx,
  input [7:0] data_in,
  input send_data,
  input send_enable,

  // 接收端口
  input rx,
  output [7:0] data_out,
  output reg data_valid,

  // 控制端口
  input [1:0] baud_rate,
  input [7:0] data_threshold,
  output reg tx_busy,
  output reg rx_full,
  output reg rx_overflow
);

// FIFO深度
localparam FIFO_DEPTH = 16;

// 定义FIFO状态和数据宽度
typedef struct {
  reg [7:0] data;
  reg valid;
} fifo_entry_t;

// 定义FIFO数组
reg [FIFO_DEPTH-1:0] fifo_ptr;
fifo_entry_t fifo[FIFO_DEPTH];

// 初始化FIFO指针
initial begin
  fifo_ptr = 0;
end

// 发送状态机
reg [3:0] send_state;
localparam SEND_IDLE = 4'd0;
localparam SEND_START = 4'd1;
localparam SEND_DATA = 4'd2;
localparam SEND_PARITY = 4'd3;
localparam SEND_STOP = 4'd4;
reg send_parity;
reg send_stop;

// 发送寄存器
reg [7:0] send_data_reg;
reg [3:0] send_bits_left;

// 初始化发送状态机
always @(posedge clk) begin
  if (reset) begin
    send_state <= SEND_IDLE;
  end else begin
    case (send_state)
      SEND_IDLE: begin
        if (send_enable) begin
          tx <= 0;
          send_data_reg <= data_in;
          send_bits_left <= 8;
          send_parity <= 1;
          send_stop <= 1;
          send_state <= SEND_START;
        end
      end
      SEND_START: begin
        tx <= 0;
        send_state <= SEND_DATA;
      end
      SEND_DATA: begin
        tx <= send_data_reg[0];
        send_data_reg <= {send_data_reg[6:0], 0};
        send_parity <= ~send_parity;
        send_bits_left <= send_bits_left - 1;
        if (send_bits_left == 0) begin
          send_state <= SEND_PARITY;
        end
      end
      SEND_PARITY: begin
        tx <= send_parity;
        send_state <= SEND_STOP;
      end
      SEND_STOP: begin
        tx <= send_stop;
        send_state <= SEND_IDLE;
      end
    endcase
  end
end

// 接收状态机
reg [3:0] recv_state;
localparam RECV_IDLE = 4'd0;
localparam RECV_START = 4'd1;
localparam RECV_DATA = 4'd2;
localparam RECV_PARITY = 4'd3;
localparam RECV_STOP = 4'd4;
reg recv_parity;
reg recv_stop;

// 接收寄存器
reg [7:0] recv_data_in;

// 初始化接收状态机
always @(posedge clk) begin
  if (reset) begin
    recv_state <= RECV_IDLE;
    data_valid <= 0;
  end else begin
    case (recv_state)
      RECV_IDLE: begin
        if (!rx) begin
          recv_state <= RECV_START;
          recv_data_in <= 0;
          recv_parity <= 1;
          recv_stop <= 1;
        end
      end
      RECV_START: begin
        recv_state <= RECV_DATA;
      end
      RECV_DATA: begin
        recv_data_in <= {recv_data_in[6:0], rx};
        recv_parity <= ~recv_parity;
        recv_state <= RECV_PARITY;
      end
      RECV_PARITY: begin
        if (recv_parity == rx) begin
          recv_state <= RECV_STOP;
        end else begin
          recv_state <= RECV_IDLE;
          rx_overflow <= 1;
        end
      end
      RECV_STOP: begin
        recv_stop <= rx;
        recv_state <= RECV_IDLE;
        if (fifo_ptr != FIFO_DEPTH-1) begin
          fifo[fifo_ptr].data <= recv_data_in;
          fifo[fifo_ptr].valid <= 1;
          fifo_ptr <= fifo_ptr + 1;
        end else begin
          rx_full <= 1;
        end
      end
    endcase
    if (fifo_ptr <= data_threshold) begin
      rx_full <= 0;
    end
  end
end

// 从FIFO中提取数据
always @(posedge clk) begin
  if (reset) begin
    data_out <= 0;
    data_valid <= 0;
  end else begin
    if (fifo[fifo_ptr].valid) begin
      data_valid <= 1;
      data_out <= fifo[fifo_ptr].data;
      fifo[fifo_ptr].valid <= 0;
      fifo_ptr <= (fifo_ptr == FIFO_DEPTH-1) ? 0 : fifo_ptr + 1;
    end else begin
      data_valid <= 0;
    end
  end
end

// 通过波特率计算发送时钟周期
reg [7:0] baud_cycles;
always @* begin
  case (baud_rate)
    2'd0: baud_cycles = 10416;
    2'd1: baud_cycles = 5208;
    2'd2: baud_cycles = 2604;
    2'd3: baud_cycles = 1302;
  endcase
end

// 发送时钟计数器
reg [7:0] send_clk_count;

// 发送模块
always @(posedge clk) begin
  if (reset) begin
    send_clk_count <= 0;
    tx_busy <= 0;
  end else begin
    if (send_enable) begin
      if (send_clk_count < baud_cycles) begin
        send_clk_count <= send_clk_count + 1;
      end else begin
        send_clk_count <= 0;
      end
      tx_busy <= 1;
    end else begin
      send_clk_count <= 0;
      tx_busy <= 0;
    end
  end
end

endmodule


// 测试代码

module uart_test;

// 时钟模块
reg clk;
always #5 clk = ~clk;

// 重置模块
reg reset;
initial begin
  reset = 1;
  #10 reset = 0;
end

// UART模块
wire tx;
wire [7:0] data_out;
wire data_valid;
wire rx;
wire tx_busy;
wire rx_full;
wire rx_overflow;
reg [7:0] data_in;
reg send_data;
reg send_enable;
reg [1:0] baud_rate;
reg [7:0] data_threshold;
uart dut(
  .clk(clk),
  .reset(reset),
  .tx(tx),
  .data_in(data_in),
  .send_data(send_data),
  .send_enable(send_enable),
  .rx(rx),
  .data_out(data_out),
  .data_valid(data_valid),
  .baud_rate(baud_rate),
  .data_threshold(data_threshold),
  .tx_busy(tx_busy),
  .rx_full(rx_full),
  .rx_overflow(rx_overflow)
);

// 发送数据
initial begin
  // 发送一个字节
  send_data = 1;
  send_enable = 1;
  data_in = 8'h57;
  #500;
  send_enable = 0;
  // 发送另一个字节
  send_data = 1;
  send_enable = 1;
  data_in = 8'hAB;
  #500;
  send_enable = 0;
end

// 模拟接收数据
initial begin
  // 第一个字节
  #1000;
  assert(data_valid);
  assert(data_out == 8'h57);
  #10;
  assert(!data_valid);
  // 第二个字节
  #1000;
  assert(data_valid);
  assert(data_out == 8'hAB);
  #10;
  assert(!data_valid);
  // 结束测试
  #1000 $finish;
end

endmodule

该代码实现了一个带有16字节FIFO的UART发送器和接收器以及一个控制模块。发送器和接收器使用状态机来解码和编码字节，并将它们存储在FIFO中。控制模块负责生成发送时钟，并监视FIFO的状态以检测接收器的溢出和FIFO的满状态。在测试代码中，发送两个字节并验证接收器是否正确接收它们。

uart带fifo的verilog

下面是一个基本的带FIFO的UART Verilog代码示例：

module uart_with_fifo(
    input clk,
    input reset,
    input rx,
    output tx,
    input [7:0] data_in,
    output [7:0] data_out,
    input write,
    input read,
    input clk_en
);

parameter BAUD_RATE = 9600; // 波特率
parameter CLK_FREQ = 50000000; // 时钟频率

parameter FIFO_DEPTH = 16; // FIFO深度

reg [7:0] fifo[FIFO_DEPTH-1:0];
reg [3:0] write_ptr = 0;
reg [3:0] read_ptr = 0;
reg [3:0] fifo_count = 0;

reg [3:0] bit_count = 0;
reg [7:0] shift_reg = 0;
reg tx_enable = 1;

assign tx = ~tx_enable;

// baud rate generator
reg [15:0] baud_tick = 0;
reg [15:0] baud_tick_max = CLK_FREQ / BAUD_RATE / 16;

always @(posedge clk) begin
    if (reset) begin
        baud_tick <= 0;
    end else if (baud_tick == baud_tick_max - 1) begin
        baud_tick <= 0;
    end else begin
        baud_tick <= baud_tick + 1;
    end
end

// tx state machine
reg [1:0] tx_state = 0;
parameter TX_IDLE = 0;
parameter TX_START = 1;
parameter TX_DATA = 2;
parameter TX_STOP = 3;

always @(posedge clk) begin
    if (reset) begin
        tx_state <= TX_IDLE;
        bit_count <= 0;
        shift_reg <= 0;
        tx_enable <= 1;
    end else begin
        case (tx_state)
            TX_IDLE:
                if (write && fifo_count > 0 && tx_enable) begin
                    tx_state <= TX_START;
                    shift_reg <= 0;
                    shift_reg[0] <= 0;
                    shift_reg[7:1] <= fifo[read_ptr];
                    read_ptr <= read_ptr + 1;
                    if (read_ptr == FIFO_DEPTH) begin
                        read_ptr <= 0;
                    end
                    fifo_count <= fifo_count - 1;
                    tx_enable <= 0;
                end else begin
                    tx_state <= TX_IDLE;
                end
            TX_START:
                tx_state <= TX_DATA;
                bit_count <= 0;
            TX_DATA:
                if (bit_count < 8) begin
                    shift_reg <= {shift_reg[6:0], data_in[bit_count]};
                    bit_count <= bit_count + 1;
                    tx_state <= TX_DATA;
                end else begin
                    tx_state <= TX_STOP;
                end
            TX_STOP:
                tx_state <= TX_IDLE;
                tx_enable <= 1;
        endcase
    end
end

// rx state machine
reg [2:0] rx_state = 0;
parameter RX_IDLE = 0;
parameter RX_START = 1;
parameter RX_DATA = 2;
parameter RX_STOP = 3;

reg [7:0] rx_data = 0;
reg rx_enable = 0;

always @(posedge clk) begin
    if (reset) begin
        rx_state <= RX_IDLE;
        rx_data <= 0;
    end else begin
        case (rx_state)
            RX_IDLE:
                if (rx == 0) begin
                    rx_state <= RX_START;
                    bit_count <= 0;
                    shift_reg <= 0;
                end else begin
                    rx_state <= RX_IDLE;
                end
            RX_START:
                rx_state <= RX_DATA;
                bit_count <= 0;
            RX_DATA:
                if (bit_count < 8) begin
                    shift_reg <= {shift_reg[6:0], rx};
                    bit_count <= bit_count + 1;
                    rx_state <= RX_DATA;
                end else begin
                    rx_state <= RX_STOP;
                end
            RX_STOP:
                rx_state <= RX_IDLE;
                if (rx == 1) begin
                    rx_data <= shift_reg;
                    rx_enable <= 1;
                end else begin
                    rx_enable <= 0;
                end
        endcase
    end
end

// fifo
always @(posedge clk) begin
    if (reset) begin
        write_ptr <= 0;
        read_ptr <= 0;
        fifo_count <= 0;
    end else begin
        if (clk_en) begin
            if (write && fifo_count < FIFO_DEPTH) begin
                fifo[write_ptr] <= data_in;
                write_ptr <= write_ptr + 1;
                if (write_ptr == FIFO_DEPTH) begin
                    write_ptr <= 0;
                end
                fifo_count <= fifo_count + 1;
            end else if (read && fifo_count > 0) begin
                read_ptr <= read_ptr + 1;
                if (read_ptr == FIFO_DEPTH) begin
                    read_ptr <= 0;
                end
                fifo_count <= fifo_count - 1;
            end
        end
    end
end

// data in/out
assign data_out = rx_data;
assign tx_enable = (tx_state == TX_IDLE) && (fifo_count > 0);

endmodule

此代码实现了一个带有FIFO缓冲区的UART模块，可以通过读/写接口向FIFO缓冲区中写入/读取字节，并通过tx和rx接口进行串口通信。它还包括一个波特率发生器和一个状态机来实现数据的传输和接收。需要注意的是，此代码是一种基本实现，您需要根据您的特定需求进行修改和调整。