`resetall`timescale 1ns/100ps`define TOTAL_BITS   11`define EXTEND_CODE  16'hE0    //擴展碼`define RELEASE_CODE 16'hF0    //釋放碼`define LEFT_SHIFT   16'h12    //左`define RIGHT_SHIFT  16'h59    //右module ps2_keyboard(  clk,                 //主時鐘  reset,               //復位==1  ps2_clk,          ps2_data,  rx_extended,         //擴展鍵(AIT CTRL windows )  rx_released,         //按鍵釋放=1  rx_shift_key_on,     //shift鍵按下=1  rx_scan_code,        //掃描碼  rx_ascii,            //ascii碼  rx_data_ready,       // rx_read_o讀數(shù)據(jù)就緒標志==1  rx_read,             // rx_read_ack_i讀信號==1  tx_data,             //寫數(shù)據(jù)bus  tx_write,            //寫信號==1  tx_write_ack_o,      //寫應答信號  tx_error_no_keyboard_ack//寫錯誤鍵盤應答  );// Parameters// The timer value can be up to (2^bits) inclusive.parameter TIMER_60USEC_VALUE_PP = 2950; // Number of sys_clks for 60usec.(clk/TIMER_60USEC_VALUE_PP≈16949hz)parameter TIMER_60USEC_BITS_PP  = 12;   // Number of bits needed for timerparameter TIMER_5USEC_VALUE_PP = 186;   // Number of sys_clks for debounce(clk/TIMER_5USEC_VALUE_PP≈268817)parameter TIMER_5USEC_BITS_PP  = 8;     // Number of bits needed for timerparameter TRAP_SHIFT_KEYS_PP = 0;       // Default: No shift key trap.// State encodings, provided as parameters// for flexibility to the one instantiating the module.// In general, the default values need not be changed.// State "m1_rx_clk_l" has been chosen on purpose.  Since the input// synchronizing flip-flops initially contain zero, it takes one clk// for them to update to reflect the actual (idle = high) status of// the I/O lines from the keyboard.  Therefore, choosing 0 for m1_rx_clk_l// allows the state machine to transition to m1_rx_clk_h when the true// values of the input signals become present at the outputs of the// synchronizing flip-flops.  This initial transition is harmless, and it// eliminates the need for a "reset" pulse before the interface can operate.parameter m1_rx_clk_h = 1;parameter m1_rx_clk_l = 0;parameter m1_rx_falling_edge_marker = 13;parameter m1_rx_rising_edge_marker = 14;parameter m1_tx_force_clk_l = 3;parameter m1_tx_first_wait_clk_h = 10;parameter m1_tx_first_wait_clk_l = 11;parameter m1_tx_reset_timer = 12;parameter m1_tx_wait_clk_h = 2;parameter m1_tx_clk_h = 4;parameter m1_tx_clk_l = 5;parameter m1_tx_wait_keyboard_ack = 6;parameter m1_tx_done_recovery = 7;parameter m1_tx_error_no_keyboard_ack = 8;parameter m1_tx_rising_edge_marker = 9;parameter m2_rx_data_ready = 1;parameter m2_rx_data_ready_ack = 0;  // I/O declarationsinput clk;input reset;inout ps2_clk;inout ps2_data;output rx_extended;output rx_released;output rx_shift_key_on;output [7:0] rx_scan_code;output [7:0] rx_ascii;output rx_data_ready;input rx_read;input [7:0] tx_data;input tx_write;output tx_write_ack_o;output tx_error_no_keyboard_ack;reg rx_extended;reg rx_released;reg [7:0] rx_scan_code;reg [7:0] rx_ascii;reg rx_data_ready;reg tx_error_no_keyboard_ack;// Internal signal declarationswire timer_60usec_done;wire timer_5usec_done;wire extended;wire released;wire shift_key_on;                         // NOTE: These two signals used to be one.  They                         //       were split into two signals because of                         //       shift key trapping.  With shift key                         //       trapping, no event is generated externally,                         //       but the "hold" data must still be cleared                         //       anyway regardless, in preparation for the                         //       next scan codes.wire rx_output_event;    // Used only to clear: hold_released, hold_extendedwire rx_output_strobe;   // Used to produce the actual output.wire tx_parity_bit;wire rx_shifting_done;wire tx_shifting_done;wire [11:0] shift_key_plus_code;reg [`TOTAL_BITS-1:0] q;reg [3:0] m1_state;reg [3:0] m1_next_state;reg m2_state;         //當前狀態(tài)reg m2_next_state;    //下一狀態(tài)reg [3:0] bit_count; //移位計數(shù)器reg enable_timer_60usec;reg enable_timer_5usec;reg [TIMER_60USEC_BITS_PP-1:0] timer_60usec_count;reg [TIMER_5USEC_BITS_PP-1:0] timer_5usec_count;reg [7:0] ascii;      // "REG" type only because a case statement is used.reg left_shift_key;reg right_shift_key;reg hold_extended;    // Holds prior value, cleared at rx_output_strobereg hold_released;    // Holds prior value, cleared at rx_output_strobereg ps2_clk_s;        // Synchronous version of this inputreg ps2_data_s;       // Synchronous version of this inputreg ps2_clk_hi_z;     // Without keyboard, high Z equals 1 due to pullups.reg ps2_data_hi_z;    // Without keyboard, high Z equals 1 due to pullups.//--------------------------------------------------------------------------// Module codeassign ps2_clk  = ps2_clk_hi_z?  1'bZ : 1'b0;assign ps2_data = ps2_data_hi_z? 1'bZ : 1'b0;// Input "synchronizing" logic -- synchronizes the inputs to the state// machine clock, thus avoiding errors related to// spurious state machine transitions.always @(posedge clk)begin  ps2_clk_s <= ps2_clk;  ps2_data_s <= ps2_data;end// State registeralways @(posedge clk)begin : m1_state_register  if (reset) m1_state <= m1_rx_clk_h;  else m1_state <= m1_next_state;end// State transition logicalways @(m1_state or q or tx_shifting_done or tx_write or ps2_clk_s or ps2_data_s or timer_60usec_done or timer_5usec_done )begin : m1_state_logic  // Output signals default to this value, unless changed in a state condition.          ps2_clk_hi_z <= 1;          ps2_data_hi_z <= 1;          tx_error_no_keyboard_ack <= 0;          enable_timer_60usec <= 0;          enable_timer_5usec <= 0;  case (m1_state)    m1_rx_clk_h :                    begin                      enable_timer_60usec <= 1;              //清除60usec計時                      if (tx_write)                          //如果有寫                      	  m1_next_state <= m1_tx_reset_timer;                            else if (~ps2_clk_s)                   //如果底電平                      	m1_next_state <= m1_rx_falling_edge_marker;//                      else m1_next_state <= m1_rx_clk_h;                    end          m1_rx_falling_edge_marker ://rx底電平處理                    begin                      enable_timer_60usec <= 0; //開始計時                      m1_next_state <= m1_rx_clk_l;                    end    m1_rx_rising_edge_marker :                    begin                      enable_timer_60usec <= 0;                      m1_next_state <= m1_rx_clk_h;                    end    m1_rx_clk_l :                   begin                     enable_timer_60usec <= 1;                     if (tx_write) m1_next_state <= m1_tx_reset_timer;                     else if (ps2_clk_s) m1_next_state <= m1_rx_rising_edge_marker;                     else m1_next_state <= m1_rx_clk_l;                   end    m1_tx_reset_timer:                   begin                     enable_timer_60usec <= 0;                     m1_next_state <= m1_tx_force_clk_l;                   end    m1_tx_force_clk_l :                   begin                     enable_timer_60usec <= 1;                     ps2_clk_hi_z <= 0;  // Force the ps2_clk line low.                     if (timer_60usec_done) m1_next_state <= m1_tx_first_wait_clk_h;                     else m1_next_state <= m1_tx_force_clk_l;                   end    m1_tx_first_wait_clk_h :                   begin                     enable_timer_5usec <= 1;                     ps2_data_hi_z <= 0;        // Start bit.                     if (~ps2_clk_s && timer_5usec_done)                       m1_next_state <= m1_tx_clk_l;                     else                       m1_next_state <= m1_tx_first_wait_clk_h;                   end          // This state must be included because the device might possibly    // delay for up to 10 milliseconds before beginning its clock pulses.    // During that waiting time, we cannot drive the data (q[0]) because it    // is possibly 1, which would cause the keyboard to abort its receive    // and the expected clocks would then never be generated.    m1_tx_first_wait_clk_l :                       begin                         ps2_data_hi_z <= 0;                         if (~ps2_clk_s) m1_next_state <= m1_tx_clk_l;                         else m1_next_state <= m1_tx_first_wait_clk_l;                       end    m1_tx_wait_clk_h :                       begin                         enable_timer_5usec <= 1;                         ps2_data_hi_z <= q[0];                         if (ps2_clk_s && timer_5usec_done)                           m1_next_state <= m1_tx_rising_edge_marker;                         else                           m1_next_state <= m1_tx_wait_clk_h;                       end    m1_tx_rising_edge_marker :                       begin                         ps2_data_hi_z <= q[0];                         m1_next_state <= m1_tx_clk_h;                       end    m1_tx_clk_h :                     begin                       ps2_data_hi_z <= q[0];                       if (tx_shifting_done) m1_next_state <= m1_tx_wait_keyboard_ack;                       else if (~ps2_clk_s) m1_next_state <= m1_tx_clk_l;                       else m1_next_state <= m1_tx_clk_h;                     end    m1_tx_clk_l :                     begin                       ps2_data_hi_z <= q[0];                       if (ps2_clk_s) m1_next_state <= m1_tx_wait_clk_h;                       else m1_next_state <= m1_tx_clk_l;                     end    m1_tx_wait_keyboard_ack :                     begin                       if (~ps2_clk_s && ps2_data_s)                         m1_next_state <= m1_tx_error_no_keyboard_ack;                       else if (~ps2_clk_s && ~ps2_data_s)                         m1_next_state <= m1_tx_done_recovery;                       else m1_next_state <= m1_tx_wait_keyboard_ack;                     end    m1_tx_done_recovery :                      begin                        if (ps2_clk_s && ps2_data_s) m1_next_state <= m1_rx_clk_h;                        else m1_next_state <= m1_tx_done_recovery;                      end    m1_tx_error_no_keyboard_ack :                     begin                       tx_error_no_keyboard_ack <= 1;                       if (ps2_clk_s && ps2_data_s) m1_next_state <= m1_rx_clk_h;                       else m1_next_state <= m1_tx_error_no_keyboard_ack;                     end