一、波形變換需求

二、思路

（1）脈沖邊沿提取，得到波形的上升沿r_rise和下降沿r_fall

（2）將上升沿r_rise延遲一節(jié)拍r_r_rise，r_rise更新上一周期的周期和脈寬并清空上一次的脈沖周期計數(shù)和脈寬周期計數(shù)，r_r_rise啟動本次脈沖周期計數(shù)和脈寬計數(shù)，r_fall結(jié)束本次脈寬計數(shù)

三、代碼

`timescale 1ns / 1ps module pulse_transfer(ttl_in ,// mcu ttl inputsys_clk ,// 100MHz clk inputreset_n ,// negtive reset inputttl_out, // fpga ttl output );/*! -------------------------------------------------------------------------- */ /*! module port defination */ input ttl_in ; input sys_clk ; input reset_n ; output ttl_out ;parameter FRE_SYS = 30'd100000000;//100MHz/*! -------------------------------------------------------------------------- */ /*! module macro defination */ parameter MAX_PULSE_WIDTH_COUNT = 16'd20000; /*! max width 200us = 10ns*20000 */ parameter MAX_PULSE_PERIOD_COUNT = 30'd100000000; /*! max period 1s */ parameter COUNT_OFFSET = 3'd2; parameter TIME_1US = 8'd100; parameter TIME_300NS = 8'd30;/*! -------------------------------------------------------------------------- */ /*! get rise and fall edge */ wire w_is_rise_trigger; wire w_is_fall_trigger; reg r_ttl_in_delay; reg r_ttl_in_delay_1; always @ ( posedge sys_clk or negedge reset_n ) beginif( !reset_n ) beginr_ttl_in_delay <= 1'b0 ;r_ttl_in_delay_1 <= 1'b0 ;endelsebeginr_ttl_in_delay <= ttl_in ;r_ttl_in_delay_1 <= r_ttl_in_delay ;end end //assign w_is_rise_trigger = ~r_ttl_in_delay&ttl_in; //assign w_is_fall_trigger = ~ttl_in&r_ttl_in_delay;/*! -------------------------------------------------------------------------- */ /*! synch rise and fall trigger */ reg r_is_rise_trigger; reg r_is_fall_trigger; always @ ( posedge sys_clk or negedge reset_n) beginif( !reset_n ) beginr_is_rise_trigger <= 1'b0;r_is_fall_trigger <= 1'b0;endelse if({r_ttl_in_delay,r_ttl_in_delay_1} == 2b'10)beginr_is_rise_trigger <= 1'b1;r_is_fall_trigger <= 1'b0;endelse if({r_ttl_in_delay,r_ttl_in_delay_1} == 2b'01)beginr_is_rise_trigger <= 1'b0;r_is_fall_trigger <= 1'b1;endelse beginr_is_rise_trigger <= 1'b0;r_is_fall_trigger <= 1'b0;end end/*! -------------------------------------------------------------------------- */ /*! get start count trigger */ reg r_count_start_trigger; wire w_count_clear_trigger; assign w_count_clear_trigger = r_is_rise_trigger; always @ ( posedge sys_clk or negedge reset_n ) beginif( !reset_n ) r_count_start_trigger <= 1'b0;elser_count_start_trigger <= w_count_clear_trigger; end /*! -------------------------------------------------------------------------- */ /*! get period and width count enable flag */ reg r_is_pulse_period_count_enable; reg r_is_pulse_width_count_enable; always @ ( posedge sys_clk or negedge reset_n) beginif( !reset_n ) beginr_is_pulse_period_count_enable = 1'b0;r_is_pulse_width_count_enable = 1'b0;endelse beginif( r_is_rise_trigger )beginr_is_pulse_period_count_enable = 1'b0;r_is_pulse_width_count_enable = 1'b0;endif( r_count_start_trigger )beginr_is_pulse_width_count_enable = 1'b1;r_is_pulse_period_count_enable = 1'b1;endif( r_is_fall_trigger )r_is_pulse_width_count_enable = 1'b0;end end /*! -------------------------------------------------------------------------- */ /*! pulse width and period count handle */ reg [30:0] r_pulse_period_count; reg [30:0] r_pulse_period; reg [30:0] r_pulse_width_count; reg [30:0] r_pulse_width; always @ ( posedge sys_clk or negedge reset_n ) beginif( !reset_n ) beginr_pulse_width_count <= 30'd0;r_pulse_width <= 30'd0;r_pulse_period_count <= 30'd0;r_pulse_period <= 30'd0;endelsebeginif( r_is_rise_trigger )begin r_pulse_period_count <= 30'd0;r_pulse_width_count <= 30'd0;endif( r_is_pulse_width_count_enable )r_pulse_width_count <= r_pulse_width_count + 1'b1;elsebeginr_pulse_width <= r_pulse_width_count;endif( r_is_pulse_period_count_enable )r_pulse_period_count <= r_pulse_period_count + 1'b1;elsebeginr_pulse_period <= r_pulse_period_count;endend end/*! -------------------------------------------------------------------------- */ /*! output pulse handle */ reg [30:0] r_out_cnt; reg r_ttl_out; always @ ( posedge sys_clk or negedge reset_n ) beginif( !reset_n ) beginr_ttl_out <= 1'b0;r_out_cnt <= 1'b0;endelsebegin//if( r_pulse_period > MAX_PULSE_PERIOD_COUNT || r_pulse_width > MAX_PULSE_WIDTH_COUNT)// begin// r_ttl_out <= 1'b0;// r_out_cnt <= 1'b0;// end//elseif(r_pulse_period == 0 || r_pulse_width == 0)beginr_out_cnt <= 1'b0;endelsebeginif( r_pulse_width <= TIME_1US + 4'd10 )//*note in <1.1us casebeginif( r_out_cnt < TIME_300NS )//0.3usbeginr_ttl_out <= 1'b1;r_out_cnt <= r_out_cnt + 1'b1;endelse if ( r_out_cnt < r_pulse_period )beginr_ttl_out <= 1'b0;r_out_cnt <= r_out_cnt + 1'b1; endelsebeginr_ttl_out <= 1'b0; r_out_cnt <= 1'b0; endendelsebeginif( r_out_cnt < r_pulse_width - TIME_1US)//*note -1usbeginr_ttl_out <= 1'b1;r_out_cnt <= r_out_cnt + 1'b1;endelse if ( r_out_cnt < r_pulse_period )beginr_ttl_out <= 1'b0;r_out_cnt <= r_out_cnt + 1'b1; endelsebeginr_ttl_out <= 1'b0; r_out_cnt <= 1'b0; endendendend end/*! -------------------------------------------------------------------------- */ /*! output assign handle */ assign ttl_out = r_ttl_out;endmodule

四、行為仿真

總結(jié)

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