verilog code for spi controlling ADC

下面是一个简单的 Verilog 代码示例，用于控制 SPI ADC：

module spi_controller(
    input clk,
    input reset,
    input start_conversion,
    output reg spi_cs_n,
    output reg spi_sclk,
    output reg spi_mosi,
    input spi_miso,
    output reg [15:0] adc_data
);

// SPI状态机定义
parameter IDLE = 2'b00;
parameter START = 2'b01;
parameter READ = 2'b10;
parameter WRITE = 2'b11;

reg [1:0] spi_state = IDLE;
reg [7:0] spi_counter = 8'h00;
reg [15:0] spi_data_out = 16'h0000;
reg [15:0] spi_data_in = 16'h0000;

// SPI控制器主逻辑
always @(posedge clk) begin
    if (reset) begin
        spi_state <= IDLE;
        spi_counter <= 8'h00;
        spi_data_out <= 16'h0000;
        spi_data_in <= 16'h0000;
        spi_cs_n <= 1'b1;
        spi_sclk <= 1'b0;
        spi_mosi <= 1'b0;
        adc_data <= 16'h0000;
    end else begin
        case (spi_state)
            IDLE: begin
                if (start_conversion) begin
                    spi_state <= START;
                end else begin
                    spi_state <= IDLE;
                end
            end
            START: begin
                spi_cs_n <= 1'b0;
                spi_sclk <= 1'b0;
                spi_mosi <= 1'b1;
                spi_data_out <= 16'h6800; // 读取通道0的命令
                spi_counter <= 8'h00;
                spi_state <= WRITE;
            end
            WRITE: begin
                spi_mosi <= spi_data_out[spi_counter];
                spi_sclk <= 1'b1;
                spi_counter <= spi_counter + 1;
                if (spi_counter == 8'h08) begin
                    spi_sclk <= 1'b0;
                    spi_counter <= 8'h00;
                    spi_state <= READ;
                end
            end
            READ: begin
                spi_sclk <= 1'b1;
                spi_data_in[spi_counter] <= spi_miso;
                spi_counter <= spi_counter + 1;
                if (spi_counter == 8'h08) begin
                    spi_sclk <= 1'b0;
                    spi_counter <= 8'h00;
                    spi_cs_n <= 1'b1;
                    adc_data <= spi_data_in[15:0]; // 将ADC数据存储到输出端口
                    spi_state <= IDLE;
                end
            end
        endcase
    end
end

endmodule

该代码实现了一个基本的 SPI 控制器，用于控制 ADC 的数据转换和读取。在这个例子中，控制器可以读取通道0的ADC数据，但您可以根据需要修改代码以适应其他通道或配置。