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@ -10,13 +10,18 @@ parameter I2C_CLK_DIV = 5'd24,
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MAX = 10'd1000,
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SLAVE_ID = 7'h73;
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//状态机参数定义
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parameter IDLE = 3'd0,
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START = 3'd1,
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SLAVE_ADDR= 3'd2,
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WAIT = 3'd3,
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STOP = 3'd4;
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reg [2: 0] state_c;
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reg [2: 0] state_n;
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parameter IDLE = 4'd0,
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START = 4'd1,
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SLAVE_ADDR = 4'd2,
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ACK_1 = 4'd3,
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ACK_2 = 4'd4,
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ACK_3 = 4'd5,
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DEVICE_ADDR = 4'd6,
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DATA = 4'd7,
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WAIT = 4'd8,
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STOP = 4'd9;
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reg [3: 0] state_c;
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reg [3: 0] state_n;
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////
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//i2c时钟计数器
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@ -26,7 +31,8 @@ reg i2c_clk;
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//中间信号定义
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reg [9: 0] cnt_wait ;//1000us
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reg skip_en_1 ;//跳转信号
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reg skip_en_1 ;//步骤1跳转信号
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reg skip_en_2 ;//步骤2跳转信号
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reg [2: 0] step ;//步骤
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reg [1: 0] cnt_i2c_clk ;//i2c计数器
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reg [2: 0] cnt_bit ;//bit计数器
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@ -38,8 +44,9 @@ reg i2c_scl ;
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reg [7: 0] slave_addr ;
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reg [7: 0] device_addr ;
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reg [7: 0] wr_data ;
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reg ack ;//接受信号
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//三态门
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assign sda_en = 1'b1;//主机控制从机
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assign sda_en = ((state_c == ACK_1) || (state_c == ACK_2) || (state_c == ACK_3)) ? 1'b0: 1'b1;//发送主机控制从机,接受主机释放
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assign sda_in = sda;
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assign sda = (sda_en == 1'b1)? i2c_sda : 1'bz;
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//i2c驱动时钟设计
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@ -79,13 +86,13 @@ end
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//状态机第二段
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always @(*)begin
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case(state_c)
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IDLE: if(skip_en_1 == 1'b1)begin
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IDLE: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
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state_n = START;
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end
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else begin
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state_n = IDLE;
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end
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START: if(skip_en_1 == 1'b1)begin
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START: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
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state_n = SLAVE_ADDR;
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end
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else begin
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@ -94,16 +101,49 @@ always @(*)begin
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SLAVE_ADDR: if(skip_en_1 == 1'b1)begin
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state_n = WAIT;
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end
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else if(skip_en_2 == 1'b1)begin
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state_n = ACK_1;
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end
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else begin
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state_n = SLAVE_ADDR;
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end
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ACK_1: if(skip_en_2 == 1'b1)begin
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state_n = DEVICE_ADDR;
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end
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else begin
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state_n = ACK_1;
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end
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DEVICE_ADDR:if(skip_en_2 == 1'b1)begin
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state_n = ACK_2;
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end
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else begin
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state_n = DEVICE_ADDR;
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end
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ACK_2: if(skip_en_2 == 1'b1)begin
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state_n = DATA;
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end
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else begin
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state_n = ACK_2;
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end
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DATA: if(skip_en_2 == 1'b1)begin
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state_n = ACK_3;
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end
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else begin
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state_n = DATA;
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end
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ACK_3: if(skip_en_2 == 1'b1)begin
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state_n = STOP;
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end
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else begin
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state_n = ACK_3;
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end
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WAIT: if(skip_en_1 == 1'b1)begin
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state_n = STOP;
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end
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else begin
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state_n = WAIT;
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end
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STOP: if(skip_en_1 == 1'b1)begin
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STOP: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
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state_n = IDLE;
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end
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else begin
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@ -119,6 +159,7 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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if(!sys_rst_n)begin
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cnt_wait <= 10'd0;
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skip_en_1 <= 1'b0;
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skip_en_2 <= 1'b0;//步骤2跳转信号
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step <= 3'd0;
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cnt_i2c_clk <= 2'd0;
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cnt_bit <= 3'd0;
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@ -127,7 +168,7 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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else begin
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case(state_c)
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IDLE: begin
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if(cnt_wait >= MAX - 1)begin
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if(cnt_wait == MAX - 1)begin
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cnt_wait <= 10'd0;
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end
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else begin
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@ -139,6 +180,12 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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else begin
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skip_en_1 <= 1'b0;
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end
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if((cnt_wait == MAX - 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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START: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
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@ -148,6 +195,12 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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else begin
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skip_en_1 <= 1'b0;
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end
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if((cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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SLAVE_ADDR: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
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@ -157,6 +210,12 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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else begin
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skip_en_1 <= 1'b0;
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end
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if((cnt_i2c_clk == 2'd2) && (step == 3'd1) && (cnt_bit == 3'd7))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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if((cnt_bit == 3'd7) && (cnt_i2c_clk == 2'd3))begin
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cnt_bit <= 3'd0;
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end
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@ -167,9 +226,72 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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cnt_bit <= cnt_bit;
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end
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end
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ACK_1: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
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if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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DEVICE_ADDR:begin
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cnt_i2c_clk <= cnt_i2c_clk + 1'b1;
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if((cnt_i2c_clk == 2'd3) && (cnt_bit == 3'd7))begin
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cnt_bit <= 3'd0;
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end
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else if(cnt_i2c_clk == 2'd3)begin
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cnt_bit <= cnt_bit + 1'b1;
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end
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else begin
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cnt_bit <= cnt_bit;
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end
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if((cnt_i2c_clk == 2'd2) && (cnt_bit == 3'd7) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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ACK_2: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1;
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if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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DATA: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1'b1;
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if((cnt_i2c_clk == 2'd3) && (cnt_bit == 3'd7))begin
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cnt_bit <= 3'd0;
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end
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else if(cnt_i2c_clk == 2'd3)begin
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cnt_bit <= cnt_bit + 1'b1;
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end
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else begin
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cnt_bit <= cnt_bit;
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end
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if((cnt_i2c_clk == 2'd2) && (cnt_bit == 3'd7) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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ACK_3: begin
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cnt_i2c_clk <= cnt_i2c_clk + 1;
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if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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end
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WAIT: begin
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if(cnt_wait == MAX - 1'd1)begin
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cnt_wait <= 10'd0;
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cnt_wait <= 10'd0;
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end
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else begin
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cnt_wait <= cnt_wait + 1'd1;
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@ -189,6 +311,12 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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else begin
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skip_en_1 <= 1'b0;
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end
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if((cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
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skip_en_2 <= 1'b1;
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end
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else begin
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skip_en_2 <= 1'b0;
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end
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if(cnt_i2c_clk == 2'd2)begin
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i2c_end <= 1'b1;
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end
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@ -205,6 +333,7 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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default: begin
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cnt_wait <= 10'd0;
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skip_en_1 <= 1'b0;
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skip_en_2 <= 1'b0;
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step <= step;
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cnt_i2c_clk <= 2'd0;
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cnt_bit <= 3'd0;
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@ -213,6 +342,13 @@ always @(posedge i2c_clk or negedge sys_rst_n)begin
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endcase
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end
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end
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//ack
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always @(*)begin
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case(state_c)
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ACK_1, ACK_2, ACK_3: ack = ~sda_in;
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default: ack = 1'b0;
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endcase
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end
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//step
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always @(*)begin
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case(step)
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@ -221,6 +357,11 @@ always @(*)begin
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device_addr = 8'h0;
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wr_data = 8'h0;
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end
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3'd1: begin
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slave_addr = {SLAVE_ID, 1'b0};
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device_addr= {8'hef};
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wr_data = {8'h00};
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end
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default:begin
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slave_addr = 8'h0;
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device_addr = 8'h0;
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@ -233,7 +374,8 @@ always @(*)begin
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case(state_c)
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IDLE: i2c_scl = 1'b1;
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START: i2c_scl = (cnt_i2c_clk <= 2'd2) ? 1'b1 : 1'b0;
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SLAVE_ADDR: i2c_scl = ((cnt_i2c_clk == 2'd1) || (cnt_i2c_clk == 2'd2)) ? 1'b1 : 1'b0;
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SLAVE_ADDR, DEVICE_ADDR, DATA, ACK_1, ACK_2, ACK_3:
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i2c_scl = ((cnt_i2c_clk == 2'd1) || (cnt_i2c_clk == 2'd2)) ? 1'b1 : 1'b0;
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WAIT: i2c_scl = 1'b0;
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STOP: i2c_scl = (cnt_i2c_clk >= 2'd1) ? 1'b1 : 1'b0;
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endcase
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@ -244,6 +386,10 @@ always @(*)begin
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IDLE: i2c_sda = 1'b1;
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START: i2c_sda = (cnt_i2c_clk > 2'd1) ? 1'b0 : 1'b1;
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SLAVE_ADDR: i2c_sda = slave_addr[7 - cnt_bit];
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DEVICE_ADDR:i2c_sda = device_addr[7 - cnt_bit];
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DATA: i2c_sda = wr_data[7 - cnt_bit];
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ACK_1, ACK_2, ACK_3:
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i2c_sda = 1'b0;
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WAIT: i2c_sda = 1'b0;
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STOP: i2c_sda = (cnt_i2c_clk >= 2'd2) ? 1'b1 : 1'b0;
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default: i2c_sda = 1'b1;
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