======基于小脚丫STEP MXO2的温度显示系统======
=====一、项目简介=====
基于小脚丫STEP MXO2的温度显示系统的核心控制模块为小脚丫STEP MXO2开发板，采用由MicroUSB输入的5V供电，温度传感器选用的是DALLAS的经典传感器——DS18B20，一个封装和常见三极管（TO-92）相同的温度传感器，而显示模块采用LCD1602，相信读者对这两个模块一定是极为熟悉。
=====二、项目框图=====
{{ ::框图.png ?600 |}}
====1.控制核心====
温度计项目控制核心为小脚丫STEP MXO2 V2版本FPGA开发板，FPGA芯片为Lattice Semiconductor的MachXO2 400HC系列FPGA。
====2.温度采集模块====
温度采集模块采用Dallas的经典产品——DS18B20，是一个高精度，占用空间小，硬件连接简单，价格低廉的数字温度传感器，采用单总线驱动方式，更为节省开发板资源。
====3.温度显示系统====
温度显示模块采用集成了ASCII字库的LCD1602，省去了自建字库的麻烦。
=====三、硬件电路图=====
{{ ::电路图.png?800 |}}
温度计的硬件电路比较简单，首先在供电方面，作为控制核心的小脚丫开发板由于具备完善的下载与供电方案，故不必在设计下载电路，只需要一根MicroUSB数据线即可满足整体系统的供电与下载；
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在温度采集部分，DS18B20共有三个引脚，我们参照硬件手册，可发现该芯片的1号引脚接地，2号引脚为数据信号DQ，接到小脚丫的任意引脚上（下图接到了小脚丫STEP MXO2的“SI”引脚上），3号引脚为电源脚，参照手册，DS18B20的输入电压为3.0V-5.5V，此处我们采用了3.3V供电。
\\
温度显示部分，LCD1602共有16个引脚，下图为LCD1602的引脚简介，对应连接即可：
{{ ::lcd1602引脚定义.png?400 |}}
=====四、Verilog代码=====
====1.Verilog代码:LCD1602显示部分====
------
// --------------------------------------------------------------------
// >>>>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// --------------------------------------------------------------------
// Module:LCD1602
//
// Author: STEP
//
// Description: Display the temperature by LCD1602
//
// Web: www.stepfpga.com
//
// --------------------------------------------------------------------
// Code Revision History :
// --------------------------------------------------------------------
// Version: |Mod. Date: |Changes Made:
// V1.0 |2017.3.8 |Initial ver
// --------------------------------------------------------------------
module LCD_1602(clk,LCD_EN,RS,RW,DB8,one_wire,rst);
input clk,rst; //系统时钟与复位，系统时钟==12M
output LCD_EN; //LCD_EN为LCD模块的使能信号（下降沿触发）
output RS; //RS=0时为写指令；RS=1时为写数据
output RW; //RW=0时对LCD模块执行写操作；RW=1时对LCD模块执行读操作
output [7:0] DB8; //8位指令或数据总线
inout one_wire; //例化DS18B20模块单总线
reg RS;
reg LCD_EN_Sel;
reg [7:0] DB8;
reg [127:0] data_row1;
reg [127:0] data_row2;
reg [7:0] result_unit;
reg [7:0] result_decade;
reg [7:0] result_hundred;
reg [7:0] result_dec;
reg [7:0] result_dec2;
reg [7:0] result_dec3;
reg [7:0] result_dec4;
reg [7:0] sign;
reg [3:0] num_unit;
reg [3:0] num_decade;
reg [3:0] num_hundred;
reg [3:0] num_dec;
reg [3:0] num_dec2;
reg [3:0] num_dec3;
reg [3:0] num_dec4; //若想显示小数点第四位，添加至显示内容并调整即可
reg[19:0] cnt_ref; //LCD1602更新计数器
reg ref; //更新标志位
always@(posedge clk_2ms) //产生LCD1602更新所需信号
begin
if(cnt_ref==220)
begin
cnt_ref<=0;
ref<=1;
ref<=0;
end
else
begin
cnt_ref<=cnt_ref+1;
ref<=1;
end
end
always@(*) //1602输入数据接口处理
begin
case(num_unit) //个位
4'd0:result_unit<=8'b00110000;
4'd1:result_unit<=8'b00110001;
4'd2:result_unit<=8'b00110010;
4'd3:result_unit<=8'b00110011;
4'd4:result_unit<=8'b00110100;
4'd5:result_unit<=8'b00110101;
4'd6:result_unit<=8'b00110110;
4'd7:result_unit<=8'b00110111;
4'd8:result_unit<=8'b00111000;
4'd9:result_unit<=8'b00111001;
default:result_unit<=result_unit;
endcase
case(num_decade) //十位
4'd0:result_decade<=8'b00110000;
4'd1:result_decade<=8'b00110001;
4'd2:result_decade<=8'b00110010;
4'd3:result_decade<=8'b00110011;
4'd4:result_decade<=8'b00110100;
4'd5:result_decade<=8'b00110101;
4'd6:result_decade<=8'b00110110;
4'd7:result_decade<=8'b00110111;
4'd8:result_decade<=8'b00111000;
4'd9:result_decade<=8'b00111001;
default:result_decade<=result_decade;
endcase
case(num_hundred) //百位
4'd0:result_hundred<=8'b00110000;
4'd1:result_hundred<=8'b00110001;
4'd2:result_hundred<=8'b00110010;
4'd3:result_hundred<=8'b00110011;
4'd4:result_hundred<=8'b00110100;
4'd5:result_hundred<=8'b00110101;
4'd6:result_hundred<=8'b00110110;
4'd7:result_hundred<=8'b00110111;
4'd8:result_hundred<=8'b00111000;
4'd9:result_hundred<=8'b00111001;
default:result_hundred<=result_hundred;
endcase
case(num_dec) //小数位
4'd0:result_dec<=8'b00110000;
4'd1:result_dec<=8'b00110001;
4'd2:result_dec<=8'b00110010;
4'd3:result_dec<=8'b00110011;
4'd4:result_dec<=8'b00110100;
4'd5:result_dec<=8'b00110101;
4'd6:result_dec<=8'b00110110;
4'd7:result_dec<=8'b00110111;
4'd8:result_dec<=8'b00111000;
4'd9:result_dec<=8'b00111001;
default:result_dec<=result_dec;
endcase
case(num_dec4) //小数位
4'd0:result_dec4<=8'b00110000;
4'd1:result_dec4<=8'b00110001;
4'd2:result_dec4<=8'b00110010;
4'd3:result_dec4<=8'b00110011;
4'd4:result_dec4<=8'b00110100;
4'd5:result_dec4<=8'b00110101;
4'd6:result_dec4<=8'b00110110;
4'd7:result_dec4<=8'b00110111;
4'd8:result_dec4<=8'b00111000;
4'd9:result_dec4<=8'b00111001;
default:result_dec4<=result_dec4;
endcase
case(num_dec2) //小数位
4'd0:result_dec2<=8'b00110000;
4'd1:result_dec2<=8'b00110001;
4'd2:result_dec2<=8'b00110010;
4'd3:result_dec2<=8'b00110011;
4'd4:result_dec2<=8'b00110100;
4'd5:result_dec2<=8'b00110101;
4'd6:result_dec2<=8'b00110110;
4'd7:result_dec2<=8'b00110111;
4'd8:result_dec2<=8'b00111000;
4'd9:result_dec2<=8'b00111001;
default:result_dec2<=result_dec2;
endcase
case(num_dec3) //小数位
4'd0:result_dec3<=8'b00110000;
4'd1:result_dec3<=8'b00110001;
4'd2:result_dec3<=8'b00110010;
4'd3:result_dec3<=8'b00110011;
4'd4:result_dec3<=8'b00110100;
4'd5:result_dec3<=8'b00110101;
4'd6:result_dec3<=8'b00110110;
4'd7:result_dec3<=8'b00110111;
4'd8:result_dec3<=8'b00111000;
4'd9:result_dec3<=8'b00111001;
default:result_dec3<=result_dec3;
endcase
end
//-------------------------------------//
//输入时钟12MHz 输出周期2ms
//division12MHz_2ms.v
reg [15:0]count;
reg clk_2ms;
always @ (posedge clk)
begin
if(count == 16'd12_000)
begin
count <= 16'b1;
clk_2ms <= ~clk_2ms;
end
else
count <= count + 1'b1;
end
//---------------------------------------//
reg [127:0] Data_Buf; //液晶显示的数据缓存
reg [4:0] disp_count;
reg [3:0] state; //状态机
parameter Clear_Lcd = 4'b0000; //清屏并光标复位
parameter Set_Disp_Mode = 4'b0001; //设置显示模式：8位2行5x7点阵
parameter Disp_On = 4'b0010; //显示器开、光标不显示、光标不允许闪烁
parameter Shift_Down = 4'b0011; //文字不动，光标自动右移
parameter Write_Addr = 4'b0100; //写入显示起始地址
parameter Write_Data_First = 4'b0101; //写入第一行显示的数据
parameter Write_Data_Second = 4'b0110; //写入第二行显示的数据
assign RW = 1'b0; //RW=0时对LCD模块执行写操作(一直保持写状态）
assign LCD_EN = LCD_EN_Sel ? clk_2ms : 1'b0; //通过LCD_EN_Sel信号来控制LCD_EN的开启与关闭
//--------------------------------显示模块----------------------------//
always @(posedge clk_2ms or negedge rst or negedge ref)
begin
//-----------------------复位并更新显示数据--------------------//
if(!rst || !ref)
begin
state <= Clear_Lcd; //复位：清屏并光标复位
RS <= 1'b1; //复位：RS=1时为读指令；
DB8 <= 8'b0; //复位：使DB8总线输出全0
LCD_EN_Sel <= 1'b0; //复位：关夜晶使能信号
disp_count <= 5'b0;
data_row1 <= { //输入第一行要显示的数据
8'b01010011, //S
8'b01010100, //T
8'b01000101, //E
8'b01010000, //P
8'b00100000, //SPACE
8'b01000110, //F
8'b01010000, //P
8'b01000111, //G
8'b01000001, //A
8'b00100000, //SPACE
8'b00100000, //SPACE
8'b00100000, //SPACE
8'b00100000, //SPACE
8'b00100000, //SPACE
8'b00100000, //SPACE
8'b00100000 //SPACE
};
data_row2 <= { 8'b00100000, //输入第二行要显示的数据
8'b00100000, //SPACE
8'b01010100, //T
8'b01100101, //e
8'b01101101, //m
8'b00111010, //冒号
sign,
result_unit,
result_decade,
result_hundred,
8'b00101110, //.
result_dec,
result_dec2,
result_dec3,
8'hdf, //℃
8'b01000011
};
end
else
begin
case(state)
//-------------------------------初始化LCD------------------------------------//
Clear_Lcd : begin LCD_EN_Sel <= 1'b1; //开使能
RS <= 1'b0; //写指令
DB8 <= 8'b00000001; //清屏并光标复位
state <= Set_Disp_Mode; end
Set_Disp_Mode : begin DB8 <= 8'b00111000; //设置显示模式：8位2行5x8点阵
state <= Disp_On; end
Disp_On : begin DB8 <= 8'b00001100; //显示器开、光标不显示、光标不允许闪烁
state <= Shift_Down; end
Shift_Down : begin DB8 <= 8'b00000110; //文字不动，光标自动右移
state <= Write_Addr; end
//---------------------------------显示循环------------------------------------//
Write_Addr : begin RS <= 1'b0; //写指令
DB8 <= 8'b10000000; //写入第一行显示起始地址：第一行第1个位置
Data_Buf <= data_row1; //将第一行显示的数据赋给Data_First_Buf
state <= Write_Data_First; end
Write_Data_First : begin //写第一行数据
if(disp_count == 16) //disp_count等于15时表示第一行数据已写完
begin
RS <= 1'b0; //写指令
DB8 <= 8'b11000000; //送入写第二行的指令,第2行第1个位置
disp_count <= 5'b0; //计数清0
Data_Buf <= data_row2; //将第2行显示的数据赋给Data_First_Buf
state <= Write_Data_Second;end //写完第一行进入写第二行状态
else //没写够16字节
begin
RS <= 1'b1; //RS=1表示写数据
DB8 <= Data_Buf[127:120];
Data_Buf <= (Data_Buf << 8);
disp_count <= disp_count + 1'b1;
state <= Write_Data_First; end end
Write_Data_Second : begin //写第二行数据
if(disp_count == 16)//数据发送完毕
begin
RS <= 1'b0; //写指令
DB8 <= 8'b10000000; //写入第一行显示起始地址：第一行第1个位置
disp_count <= 5'b0;
state <= Write_Addr; //重新循环
end
else
begin
RS <= 1'b1;
DB8 <= Data_Buf[127:120];
Data_Buf <= (Data_Buf << 8);
disp_count <= disp_count + 1'b1;
state <= Write_Data_Second;
end end
//--------------------------------------------------------------------------//
default : state <= Clear_Lcd; //若state为其他值，则将state置为Clear_Lcd
endcase
end
end
//--------------------------------------------------------------------------//
wire clk_in;
wire rst_n_in;
wire [15:0] data_out;
wire tem_flag=data_out[15:11]?1'b0:1'b1;
wire [10:0] tem_code=tem_flag?data_out[10:0]:(~data_out[10:0])+1'b1;
wire [20:0] tem_data=tem_code*625;
reg [27:0] bcd_code;
DS18B20Z DS18B20Z_uut
(
.one_wire(one_wire),
.clk_in(clk),
.rst_n_in(rst),
.data_out(data_out)
);
reg [48:0] shift_reg;
always@(posedge clk or negedge rst)begin
shift_reg= {28'h0,tem_data};
if(!rst) bcd_code = 0;
else
begin
repeat(21)//repeat B_SIZE times
begin
if (shift_reg[24:21] >= 5) shift_reg[24:21] = shift_reg[24:21] + 2'b11;
if (shift_reg[28:25] >= 5) shift_reg[28:25] = shift_reg[28:25] + 2'b11;
if (shift_reg[32:29] >= 5) shift_reg[32:29] = shift_reg[32:29] + 2'b11;
if (shift_reg[36:33] >= 5) shift_reg[36:33] = shift_reg[36:33] + 2'b11;
if (shift_reg[40:37] >= 5) shift_reg[40:37] = shift_reg[40:37] + 2'b11;
if (shift_reg[44:41] >= 5) shift_reg[44:41] = shift_reg[44:41] + 2'b11;
if (shift_reg[48:45] >= 5) shift_reg[48:45] = shift_reg[48:45] + 2'b11;
if (tem_flag==0) sign<=8'b00101101;
if (tem_flag==1) sign<=8'b00100000;
shift_reg = shift_reg << 1;
end
bcd_code=shift_reg[48:21];
num_unit <= bcd_code[27:24];
num_decade <= bcd_code[23:20];
num_hundred<= bcd_code[19:16];
num_dec <= bcd_code[15:12];
num_dec2 <= bcd_code[11:8];
num_dec3 <= bcd_code[7:4];
num_dec4 <= bcd_code[3:0];
end
end
endmodule
====2.温度采集部分====
------
// --------------------------------------------------------------------
// >>>>>>>>>>>>>>>>>>>>>>>>> COPYRIGHT NOTICE <<<<<<<<<<<<<<<<<<<<<<<<<
// --------------------------------------------------------------------
// Module:DS18B20Z
//
// Author: Step
//
// Description: Drive DS18B20Z to get temperature code
//
// Web: www.stepfpga.com
//
// --------------------------------------------------------------------
// Code Revision History :
// --------------------------------------------------------------------
// Version: |Mod. Date: |Changes Made:
// V1.0 |2015/11/11 |Initial ver
// --------------------------------------------------------------------
module DS18B20Z
(
input clk_in, // system clock
input rst_n_in, // system reset, active low
inout one_wire, // ds18b20z one-wire-bus
output reg [15:0] data_out // ds18b20z data_out
);
localparam IDLE = 3'd0;
localparam MAIN = 3'd1;
localparam INIT = 3'd2;
localparam WRITE = 3'd3;
localparam READ = 3'd4;
localparam DELAY = 3'd5;
//generate clk_1mhz clock
reg clk_1mhz;
reg [2:0] cnt_1mhz;
always@(posedge clk_in or negedge rst_n_in) begin
if(!rst_n_in) begin
cnt_1mhz <= 3'd0;
clk_1mhz <= 1'b0;
end else if(cnt_1mhz >= 3'd5) begin
cnt_1mhz <= 3'd0;
clk_1mhz <= ~clk_1mhz;
end else begin
cnt_1mhz <= cnt_1mhz + 1'b1;
end
end
reg one_wire_buffer;
reg [3:0] cnt_main;
reg [7:0] data_wr;
reg [7:0] data_wr_buffer;
reg [2:0] cnt_init;
reg [19:0] cnt_delay;
reg [19:0] num_delay;
reg [5:0] cnt_write;
reg [5:0] cnt_read;
reg [15:0] temperature;
reg [7:0] temperature_buffer;
reg [2:0] state = IDLE;
reg [2:0] state_back = IDLE;
always@(posedge clk_1mhz or negedge rst_n_in) begin
if(!rst_n_in) begin
state <= IDLE;
state_back <= IDLE;
cnt_main <= 4'd0;
cnt_init <= 3'd0;
cnt_write <= 6'd0;
cnt_read <= 6'd0;
cnt_delay <= 20'd0;
one_wire_buffer <= 1'bz;
temperature <= 16'h0;
end else begin
case(state)
IDLE:begin
state <= MAIN;
state_back <= MAIN;
cnt_main <= 4'd0;
cnt_init <= 3'd0;
cnt_write <= 6'd0;
cnt_read <= 6'd0;
cnt_delay <= 20'd0;
one_wire_buffer <= 1'bz;
end
MAIN:begin
if(cnt_main >= 4'd11) cnt_main <= 1'b0;
else cnt_main <= cnt_main + 1'b1;
case(cnt_main)
4'd0: begin state <= INIT; end
4'd1: begin data_wr <= 8'hcc;state <= WRITE; end
4'd2: begin data_wr <= 8'h44;state <= WRITE; end
4'd3: begin num_delay <= 20'd750000;state <= DELAY;state_back <= MAIN; end
4'd4: begin state <= INIT; end
4'd5: begin data_wr <= 8'hcc;state <= WRITE; end
4'd6: begin data_wr <= 8'hbe;state <= WRITE; end
4'd7: begin state <= READ; end
4'd8: begin temperature[7:0] <= temperature_buffer; end
4'd9: begin state <= READ; end
4'd10: begin temperature[15:8] <= temperature_buffer; end
4'd11: begin state <= IDLE;data_out <= temperature; end
default: state <= IDLE;
endcase
end
INIT:begin
if(cnt_init >= 3'd6) cnt_init <= 1'b0;
else cnt_init <= cnt_init + 1'b1;
case(cnt_init)
3'd0: begin one_wire_buffer <= 1'b0; end
3'd1: begin num_delay <= 20'd500;state <= DELAY;state_back <= INIT; end
3'd2: begin one_wire_buffer <= 1'bz; end
3'd3: begin num_delay <= 20'd100;state <= DELAY;state_back <= INIT; end
3'd4: begin if(one_wire) state <= IDLE; else state <= INIT; end
3'd5: begin num_delay <= 20'd400;state <= DELAY;state_back <= INIT; end
3'd6: begin state <= MAIN; end
default: state <= IDLE;
endcase
end
WRITE:begin
if(cnt_write >= 6'd50) cnt_write <= 1'b0;
else cnt_write <= cnt_write + 1'b1;
case(cnt_write)
//lock data_wr
6'd0: begin data_wr_buffer <= data_wr; end
//write bit 0
6'd1: begin one_wire_buffer <= 1'b0; end
6'd2: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd3: begin one_wire_buffer <= data_wr_buffer[0]; end
6'd4: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd5: begin one_wire_buffer <= 1'bz; end
6'd6: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 1
6'd7: begin one_wire_buffer <= 1'b0; end
6'd8: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd9: begin one_wire_buffer <= data_wr_buffer[1]; end
6'd10: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd11: begin one_wire_buffer <= 1'bz; end
6'd12: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 2
6'd13: begin one_wire_buffer <= 1'b0; end
6'd14: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd15: begin one_wire_buffer <= data_wr_buffer[2]; end
6'd16: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd17: begin one_wire_buffer <= 1'bz; end
6'd18: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 3
6'd19: begin one_wire_buffer <= 1'b0; end
6'd20: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd21: begin one_wire_buffer <= data_wr_buffer[3]; end
6'd22: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd23: begin one_wire_buffer <= 1'bz; end
6'd24: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 4
6'd25: begin one_wire_buffer <= 1'b0; end
6'd26: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd27: begin one_wire_buffer <= data_wr_buffer[4]; end
6'd28: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd29: begin one_wire_buffer <= 1'bz; end
6'd30: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 5
6'd31: begin one_wire_buffer <= 1'b0; end
6'd32: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd33: begin one_wire_buffer <= data_wr_buffer[5]; end
6'd34: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd35: begin one_wire_buffer <= 1'bz; end
6'd36: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 6
6'd37: begin one_wire_buffer <= 1'b0; end
6'd38: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd39: begin one_wire_buffer <= data_wr_buffer[6]; end
6'd40: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd41: begin one_wire_buffer <= 1'bz; end
6'd42: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//write bit 7
6'd43: begin one_wire_buffer <= 1'b0; end
6'd44: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
6'd45: begin one_wire_buffer <= data_wr_buffer[7]; end
6'd46: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd47: begin one_wire_buffer <= 1'bz; end
6'd48: begin num_delay <= 20'd2;state <= DELAY;state_back <= WRITE; end
//back to main
6'd49: begin num_delay <= 20'd80;state <= DELAY;state_back <= WRITE; end
6'd50: begin state <= MAIN; end
default: state <= IDLE;
endcase
end
READ:begin
if(cnt_read >= 6'd48) cnt_read <= 1'b0;
else cnt_read <= cnt_read + 1'b1;
case(cnt_read)
//read bit 0
6'd0: begin one_wire_buffer <= 1'b0; end
6'd1: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd2: begin one_wire_buffer <= 1'bz; end
6'd3: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd4: begin temperature_buffer[0] <= one_wire; end
6'd5: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 1
6'd6: begin one_wire_buffer <= 1'b0; end
6'd7: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd8: begin one_wire_buffer <= 1'bz; end
6'd9: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd10: begin temperature_buffer[1] <= one_wire; end
6'd11: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 2
6'd12: begin one_wire_buffer <= 1'b0; end
6'd13: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd14: begin one_wire_buffer <= 1'bz; end
6'd15: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd16: begin temperature_buffer[2] <= one_wire; end
6'd17: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 3
6'd18: begin one_wire_buffer <= 1'b0; end
6'd19: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd20: begin one_wire_buffer <= 1'bz; end
6'd21: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd22: begin temperature_buffer[3] <= one_wire; end
6'd23: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 4
6'd24: begin one_wire_buffer <= 1'b0; end
6'd25: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd26: begin one_wire_buffer <= 1'bz; end
6'd27: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd28: begin temperature_buffer[4] <= one_wire; end
6'd29: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 5
6'd30: begin one_wire_buffer <= 1'b0; end
6'd31: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd32: begin one_wire_buffer <= 1'bz; end
6'd33: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd34: begin temperature_buffer[5] <= one_wire; end
6'd35: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 6
6'd36: begin one_wire_buffer <= 1'b0; end
6'd37: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd38: begin one_wire_buffer <= 1'bz; end
6'd39: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd40: begin temperature_buffer[6] <= one_wire; end
6'd41: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//read bit 7
6'd42: begin one_wire_buffer <= 1'b0; end
6'd43: begin num_delay <= 20'd2;state <= DELAY;state_back <= READ; end
6'd44: begin one_wire_buffer <= 1'bz; end
6'd45: begin num_delay <= 20'd10;state <= DELAY;state_back <= READ; end
6'd46: begin temperature_buffer[7] <= one_wire; end
6'd47: begin num_delay <= 20'd55;state <= DELAY;state_back <= READ; end
//back to main
6'd48: begin state <= MAIN; end
default: state <= IDLE;
endcase
end
DELAY:begin
if(cnt_delay >= num_delay) begin
cnt_delay <= 1'b0;
state <= state_back;
end else cnt_delay <= cnt_delay + 1'b1;
end
endcase
end
end
assign one_wire = one_wire_buffer;
endmodule