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gesture_game/rtl/i2c_ctrl.v

399 lines
15 KiB
Verilog
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module i2c_ctrl(
input wire sys_clk ,
input wire sys_rst_n ,
output wire scl ,
inout wire sda
);
parameter I2C_CLK_DIV = 5'd24,
MAX = 10'd1000,
SLAVE_ID = 7'h73;
//状态机参数定义
parameter IDLE = 4'd0,
START = 4'd1,
SLAVE_ADDR = 4'd2,
ACK_1 = 4'd3,
ACK_2 = 4'd4,
ACK_3 = 4'd5,
DEVICE_ADDR = 4'd6,
DATA = 4'd7,
WAIT = 4'd8,
STOP = 4'd9;
reg [3: 0] state_c;
reg [3: 0] state_n;
////
//i2c时钟计数器
reg [4: 0] cnt_clk;
reg i2c_clk;
/////
//中间信号定义
reg [9: 0] cnt_wait ;//1000us
reg skip_en_1 ;//步骤1跳转信号
reg skip_en_2 ;//步骤2跳转信号
reg [2: 0] step ;//步骤
reg [1: 0] cnt_i2c_clk ;//i2c计数器
reg [2: 0] cnt_bit ;//bit计数器
reg i2c_end ;//i2c结束信号
wire sda_en ;
wire sda_in ;
reg i2c_sda ;
reg i2c_scl ;
reg [7: 0] slave_addr ;
reg [7: 0] device_addr ;
reg [7: 0] wr_data ;
reg ack ;//接受信号
//三态门
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
assign sda_in = sda;
assign sda = (sda_en == 1'b1)? i2c_sda : 1'bz;
//i2c驱动时钟设计
always @(posedge sys_clk or negedge sys_rst_n) begin
if(!sys_rst_n)begin
cnt_clk <= 5'd0;
end
else if(cnt_clk == I2C_CLK_DIV)begin
cnt_clk <= 5'd0;
end
else begin
cnt_clk <= cnt_clk + 1;
end
end
always @(posedge sys_clk or negedge sys_rst_n) begin
if(!sys_rst_n)begin
i2c_clk <= 1'b1;
end
else if(cnt_clk == I2C_CLK_DIV)begin
i2c_clk <= ~i2c_clk;
end
else begin
i2c_clk <= i2c_clk;
end
end
/////////
//状态机，第一段
always @(posedge i2c_clk or negedge sys_rst_n) begin
if(!sys_rst_n)begin
state_c <= IDLE;
end
else begin
state_c <= state_n;
end
end
//状态机第二段
always @(*)begin
case(state_c)
IDLE: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
state_n = START;
end
else begin
state_n = IDLE;
end
START: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
state_n = SLAVE_ADDR;
end
else begin
state_n = START;
end
SLAVE_ADDR: if(skip_en_1 == 1'b1)begin
state_n = WAIT;
end
else if(skip_en_2 == 1'b1)begin
state_n = ACK_1;
end
else begin
state_n = SLAVE_ADDR;
end
ACK_1: if(skip_en_2 == 1'b1)begin
state_n = DEVICE_ADDR;
end
else begin
state_n = ACK_1;
end
DEVICE_ADDR:if(skip_en_2 == 1'b1)begin
state_n = ACK_2;
end
else begin
state_n = DEVICE_ADDR;
end
ACK_2: if(skip_en_2 == 1'b1)begin
state_n = DATA;
end
else begin
state_n = ACK_2;
end
DATA: if(skip_en_2 == 1'b1)begin
state_n = ACK_3;
end
else begin
state_n = DATA;
end
ACK_3: if(skip_en_2 == 1'b1)begin
state_n = STOP;
end
else begin
state_n = ACK_3;
end
WAIT: if(skip_en_1 == 1'b1)begin
state_n = STOP;
end
else begin
state_n = WAIT;
end
STOP: if((skip_en_1 == 1'b1) || (skip_en_2 == 1'b1))begin
state_n = IDLE;
end
else begin
state_n = STOP;
end
default: begin
state_n = IDLE;
end
endcase
end
//状态机第三段
always @(posedge i2c_clk or negedge sys_rst_n)begin
if(!sys_rst_n)begin
cnt_wait <= 10'd0;
skip_en_1 <= 1'b0;
skip_en_2 <= 1'b0;//步骤2跳转信号
step <= 3'd0;
cnt_i2c_clk <= 2'd0;
cnt_bit <= 3'd0;
i2c_end <= 1'b0;
end
else begin
case(state_c)
IDLE: begin
if(cnt_wait == MAX - 1)begin
cnt_wait <= 10'd0;
end
else begin
cnt_wait <= cnt_wait + 1;
end
if((cnt_wait == MAX - 2'd2) && (step == 3'd0))begin
skip_en_1 <= 1'b1;
end
else begin
skip_en_1 <= 1'b0;
end
if((cnt_wait == MAX - 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
START: begin
cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
if((cnt_i2c_clk == 2'd2) && (step == 3'd0))begin
skip_en_1 <= 1'b1;
end
else begin
skip_en_1 <= 1'b0;
end
if((cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
SLAVE_ADDR: begin
cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
if((cnt_i2c_clk == 2'd2) && (step == 3'd0) && (cnt_bit == 3'd7))begin
skip_en_1 <= 1'b1;
end
else begin
skip_en_1 <= 1'b0;
end
if((cnt_i2c_clk == 2'd2) && (step == 3'd1) && (cnt_bit == 3'd7))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
if((cnt_bit == 3'd7) && (cnt_i2c_clk == 2'd3))begin
cnt_bit <= 3'd0;
end
else if(cnt_i2c_clk == 2'd3)begin
cnt_bit <= cnt_bit + 1'd1;
end
else begin
cnt_bit <= cnt_bit;
end
end
ACK_1: begin
cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
DEVICE_ADDR:begin
cnt_i2c_clk <= cnt_i2c_clk + 1'b1;
if((cnt_i2c_clk == 2'd3) && (cnt_bit == 3'd7))begin
cnt_bit <= 3'd0;
end
else if(cnt_i2c_clk == 2'd3)begin
cnt_bit <= cnt_bit + 1'b1;
end
else begin
cnt_bit <= cnt_bit;
end
if((cnt_i2c_clk == 2'd2) && (cnt_bit == 3'd7) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
ACK_2: begin
cnt_i2c_clk <= cnt_i2c_clk + 1;
if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
DATA: begin
cnt_i2c_clk <= cnt_i2c_clk + 1'b1;
if((cnt_i2c_clk == 2'd3) && (cnt_bit == 3'd7))begin
cnt_bit <= 3'd0;
end
else if(cnt_i2c_clk == 2'd3)begin
cnt_bit <= cnt_bit + 1'b1;
end
else begin
cnt_bit <= cnt_bit;
end
if((cnt_i2c_clk == 2'd2) && (cnt_bit == 3'd7) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
ACK_3: begin
cnt_i2c_clk <= cnt_i2c_clk + 1;
if((ack == 1'b1) && (cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
end
WAIT: begin
if(cnt_wait == MAX - 1'd1)begin
cnt_wait <= 10'd0;
end
else begin
cnt_wait <= cnt_wait + 1'd1;
end
if((cnt_wait == MAX - 2'd2) && (step == 3'd0))begin
skip_en_1 <= 1'b1;
end
else begin
skip_en_1 <= 1'b0;
end
end
STOP: begin
cnt_i2c_clk <= cnt_i2c_clk + 1'd1;
if((cnt_i2c_clk == 2'd2) && (step == 3'd0))begin
skip_en_1 <= 1'b1;
end
else begin
skip_en_1 <= 1'b0;
end
if((cnt_i2c_clk == 2'd2) && (step == 3'd1))begin
skip_en_2 <= 1'b1;
end
else begin
skip_en_2 <= 1'b0;
end
if(cnt_i2c_clk == 2'd2)begin
i2c_end <= 1'b1;
end
else begin
i2c_end <= 1'b0;
end
if(i2c_end == 1'b1)begin
step <= step + 1'd1;
end
else begin
step <= step;
end
end
default: begin
cnt_wait <= 10'd0;
skip_en_1 <= 1'b0;
skip_en_2 <= 1'b0;
step <= step;
cnt_i2c_clk <= 2'd0;
cnt_bit <= 3'd0;
i2c_end <= 1'b0;
end
endcase
end
end
//ack
always @(*)begin
case(state_c)
ACK_1, ACK_2, ACK_3: ack = ~sda_in;
default: ack = 1'b0;
endcase
end
//step
always @(*)begin
case(step)
3'd0: begin
slave_addr = {SLAVE_ID, 1'b0};
device_addr = 8'h0;
wr_data = 8'h0;
end
3'd1: begin
slave_addr = {SLAVE_ID, 1'b0};
device_addr= {8'hef};
wr_data = {8'h00};
end
default:begin
slave_addr = 8'h0;
device_addr = 8'h0;
wr_data = 8'h0;
end
endcase
end
//i2c_scl
always @(*)begin
case(state_c)
IDLE: i2c_scl = 1'b1;
START: i2c_scl = (cnt_i2c_clk <= 2'd2) ? 1'b1 : 1'b0;
SLAVE_ADDR, DEVICE_ADDR, DATA, ACK_1, ACK_2, ACK_3:
i2c_scl = ((cnt_i2c_clk == 2'd1) || (cnt_i2c_clk == 2'd2)) ? 1'b1 : 1'b0;
WAIT: i2c_scl = 1'b0;
STOP: i2c_scl = (cnt_i2c_clk >= 2'd1) ? 1'b1 : 1'b0;
endcase
end
//i2c_sda
always @(*)begin
case(state_c)
IDLE: i2c_sda = 1'b1;
START: i2c_sda = (cnt_i2c_clk > 2'd1) ? 1'b0 : 1'b1;
SLAVE_ADDR: i2c_sda = slave_addr[7 - cnt_bit];
DEVICE_ADDR:i2c_sda = device_addr[7 - cnt_bit];
DATA: i2c_sda = wr_data[7 - cnt_bit];
ACK_1, ACK_2, ACK_3:
i2c_sda = 1'b0;
WAIT: i2c_sda = 1'b0;
STOP: i2c_sda = (cnt_i2c_clk >= 2'd2) ? 1'b1 : 1'b0;
default: i2c_sda = 1'b1;
endcase
end
assign scl = i2c_scl;
endmodule
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