📲 第28课：蓝牙串口

// 蓝牙串口控制器 - HC-05透传+AT配置
module bluetooth_ctrl (
    input  wire        clk,
    input  wire        rst,
    // UART接口(蓝牙)
    output wire [7:0]  bt_tx_data,
    output wire        bt_tx_start,
    input  wire        bt_tx_busy,
    input  wire [7:0]  bt_rx_data,
    input  wire        bt_rx_valid,
    // UART接口(PC调试)
    output wire [7:0]  pc_tx_data,
    output wire        pc_tx_start,
    input  wire        pc_tx_busy,
    input  wire [7:0]  pc_rx_data,
    input  wire        pc_rx_valid,
    // 控制
    input  wire        mode,         // 0=透传, 1=AT配置
    output reg         bt_connected, // 蓝牙已连接
    output reg  [7:0]  link_status   // 连接状态LED
);
    // 透传模式: BT ↔ PC 双向转发
    assign pc_tx_data  = bt_rx_data;
    assign pc_tx_start = bt_rx_valid && !mode;
    assign bt_tx_data  = pc_rx_data;
    assign bt_tx_start = pc_rx_valid && !mode;

    // AT配置模式: 自动发送AT命令
    reg [7:0] at_cmd [0:15];
    reg [3:0] at_idx, at_step;
    reg       at_sending;
    reg [19:0] at_timer;

    initial begin
        // AT配置序列
        at_cmd[0]  = 8'h41; // A
        at_cmd[1]  = 8'h54; // T
        at_cmd[2]  = 8'h0D; // 
        at_cmd[3]  = 8'h0A; // 

        at_cmd[4]  = 8'h00; // 结束
    end

    // 连接状态检测: LED闪烁模式
    always @(posedge clk) begin
        if (rst) begin
            bt_connected <= 0; link_status <= 0;
            at_step <= 0; at_sending <= 0;
        end else begin
            // 检测蓝牙连接(收到数据=已连接)
            if (bt_rx_valid) bt_connected <= 1;

            // 连接状态LED
            at_timer <= at_timer + 1;
            if (bt_connected)
                link_status <= 8'hAA; // 快闪
            else
                link_status <= at_timer[19]; // 慢闪

            // AT模式发送
            if (mode && !at_sending) begin
                if (at_step == 0) begin
                    at_idx <= 0; at_sending <= 1;
                end
            end
        end
    end
endmodule

module bluetooth_ctrl_tb;
    logic clk=0, rst=1, mode=0;
    logic [7:0] bt_tx_data, pc_tx_data;
    logic bt_tx_start, pc_tx_start;
    logic bt_tx_busy=0, pc_tx_busy=0;
    logic [7:0] bt_rx_data=0, pc_rx_data=0;
    logic bt_rx_valid=0, pc_rx_valid=0;
    logic bt_connected;
    logic [7:0] link_status;

    bluetooth_ctrl uut(.*);
    always #10 clk = ~clk;

    initial begin
        rst=1; #50; rst=0;
        $display("--- 蓝牙控制器测试 ---");
        // 透传模式: PC→BT
        mode=0;
        pc_rx_data=8'h48; pc_rx_valid=1; #20; pc_rx_valid=0;
        #20;
        $display("  PC→BT: tx_data=0x%h (应为0x48) %s",
                 bt_tx_data, bt_tx_data==8'h48?"✓":"FAIL");
        // BT→PC
        bt_rx_data=8'h4F; bt_rx_valid=1; #20; bt_rx_valid=0;
        #20;
        $display("  BT→PC: tx_data=0x%h (应为0x4F) %s",
                 pc_tx_data, pc_tx_data==8'h4F?"✓":"FAIL");
        $display("  bt_connected=%b %s", bt_connected,
                 bt_connected?"✓":"FAIL");
        $display("蓝牙控制器测试完成 ✓");
        #100; $finish;
    end
endmodule