基于FPGA的数字时钟显示（万年历lcd1602）
一、 lcd1602a的驱动和配置
（1） lcd1602a的管脚分配图，在程序中，我们需要对相应的管脚进行操作，才能使其正确显示
（2） 由于我使用的板子EP4CE6上的晶振是50MHZ，而lcd1602a所需要的晶振是500HZ，所以我们要想驱动他，首先要产生一个500HZ的时钟，所以我定义了如下lcd时钟代码：
always@(posedge clk)//获得LCD时钟
begin
count<=count+1;
if(count==32'd50000)//2ms
begin
count<=32'b0;
lcd_clk<=~lcd_clk;
end
end
（3） 因为lcd中存储的字符是ASCII码，直接写入的字符不能被正确的写入，ASCII中’0’的地址是0x38，所以写入的字符都要加上0X38才能正确显示
two_7<=(shi/8'd10)+8'b00110000;
two_8<=(shi%8'd10)+8'b00110000;
two_10<=(fen/8'd10)+8'b0010000;
two_11<=(fen%8'd10)+8'b00110000;
two_13<=(miao/8'd10)+8'b00110000;
two_14<=(miao%8'd10)+8'b00110000;
one_1<=(year/16'd1000)+8'b00110000;
one_2<=((year%16'd1000)/16'd100)+8'b00110000;
one_3<=((year%16'd100)/8'd10)+8'b00110000;
one_4<=(year%8'd10)+8'b00110000;
one_6<=(month/8'd10)+8'b00110000;
one_7<=(month%8'd10)+8'b00110000;
one_9<=(dat/8'd10)+8'b00110000;
one_10<=(dat%8'd10)+8'b00110000;
（4） 主要lcd的完成是依托于状态机的，我定义了两种参数，一种是数据寄存器的参数，一种是指令寄存器的参数，指令寄存的参数是定义lcd的显示状态的，而数据寄存器定义的是他应该显示些什么，当对产生的lcd时钟进行操作的时候，就是一步一步执行状态中的各个状态，状态机中进行的各个状态也会对rs进行配置
parameter state0 = 8'h00,//设置8位格式,2行,5*7 8'h38
state1 = 8'h01,//整体显示,关光标,不闪烁 8'h0C闪烁 8'h0e
state2 = 8'h02,//设定输入方式,增量不移位 8'h06
state3 = 8'h03,//清除显示 8'h01
state4 = 8'h04,//显示第一行的指令 80H
state5 = 8'h05,//显示第二行的指令 80H+40H
scan = 8'h06,
nul = 8'h07;
parameter data0 = 8'h10,//2行32个数据状态data1 = 8'h11,
data2 = 8'h12,data3 = 8'h13,data4 = 8'h14,data5 = 8'h15,
data6 = 8'h16,data7 = 8'h17,data8 = 8'h18,data9 = 8'h19,
data10 = 8'h20,data11 = 8'h21,data12 = 8'h22,
data13 = 8'h23,data14 = 8'h24,data15 = 8'h25,
data16 = 8'h26,data17 = 8'h27,data18 = 8'h28,
data19 = 8'h29,data20 = 8'h30,data21 = 8'h31,
data22 = 8'h32,data23 = 8'h33,data24 = 8'h34,
data25 = 8'h35,data26 = 8'h36,data27 = 8'h37,
data28 = 8'h38,data29 = 8'h39,data30 = 8'h40,
data31 = 8'h41;
always@(posedge lcd_clk)
begin
case(next)
state0:
begin rs<=1'b0; data<=8'h38; next<=state1; end//rs高是数据寄存器，rs低是指令寄存器
state1:
begin rs<=1'b0; data<=8'h0e; next<=state2; end
state2:
begin rs<=1'b0; data<=8'h06; next<=state3; end
state3:
begin rs<=1'b0; data<=8'h01; next<=state4; end
state4:
begin rs<=1'b0; data<=8'h80; next<=data0; end//显示第一行
data0 :
begin rs<=1'b1; data<=one_1; next<=data1 ; end
data1 :
begin rs<=1'b1; data<=one_2; next<=data2 ; end
data2 :
begin rs<=1'b1; data<=one_3; next<=data3 ; end
data3 :
begin rs<=1'b1; data<=one_4; next<=data4 ; end
data4 :
begin rs<=1'b1; data<=one_5; next<=data5 ; end
data5 :
begin rs<=1'b1; data<=one_6; next<=data6 ; end
data6 :
begin rs<=1'b1; data<=one_7; next<=data7 ; end
data7 :
begin rs<=1'b1; data<=one_8; next<=data8 ; end
data8 :
begin rs<=1'b1; data<=one_9; next<=data9 ; end
data9 :
begin rs<=1'b1; data<=one_10; next<=data10 ; end
data10 :
begin rs<=1'b1; data<=one_11; next<=data11 ; end
data11 :
begin rs<=1'b1; data<=one_12; next<=data12 ; end
data12 :
begin rs<=1'b1; data<=one_13; next<=data13 ; end
data13 :
begin rs<=1'b1; data<=one_14; next<=data14 ; end
data14 :
begin rs<=1'b1; data<=one_15; next<=data15 ; end
data15 :
begin rs<=1'b1; data<=one_16; next<=state5 ; end
state5:
begin rs<=1'b0;data<=8'hC0; next<=data16; end //显示第二行
data16 :
begin rs<=1'b1; data<=two_1; next<=data17 ; end
data17 :
begin rs<=1'b1; data<=two_2; next<=data18 ; end
data18 :
begin rs<=1'b1; data<=two_3; next<=data19 ; end
data19 :
begin rs<=1'b1; data<=two_4; next<=data20 ; end
data20 :
begin rs<=1'b1; data<=two_5; next<=data21 ; end
data21 :
begin rs<=1'b1; data<=two_6; next<=data22 ; end
data22 :
begin rs<=1'b1; data<=two_7; next<=data23 ; end
data23 :
begin rs<=1'b1; data<=two_8; next<=data24 ; end
data24 :
begin rs<=1'b1; data<=two_9; next<=data25 ; end
data25 :
begin rs<=1'b1; data<=two_10; next<=data26 ; end
data26 :
begin rs<=1'b1; data<=two_11; next<=data27 ; end
data27 :
begin rs<=1'b1; data<=two_12; next<=data28 ; end
data28 :
begin rs<=1'b1; data<=two_13; next<=data29 ; end
data29 :
begin rs<=1'b1; data<=two_14; next<=data30 ; end
data30 :
begin rs<=1'b1; data<=two_15; next<=data31 ; end
data31 :
begin rs<=1'b1; data<=two_16; next<=scan ; end
scan://交替更新第一行和第二行数据
begin next<=state4; end
default: next<=state0;
endcase
end
二、时钟计时及校准
1. 判断模式
由于本开发板上只有一个三个按键，所以本工程定义的功能一个为调模式的按键，其他两个为加减按键，为了能对按键按下的次数进行相应的操作，所以我们定义了一个按键寄存器以存储相应的按键次数
//获取按键的寄存器
always@(posedge clk or negedge rst)
begin
if(!rst)
begin
flag<=4'b0;
end
else
if(key1)
begin
flag<=flag+1'b1;
if(flag==4'b1011) flag<=4'b0000;
end
end
2. 计时
这个计时是对计数器进行操作，如果计数器达到1秒，秒加1，秒到达59，分加1，以此类推，其中因为不同的月份对应的天数不同，所以事先我定义了闰年平年，大月小月的判断，根据判断值选择相应的天数
判断
// 判断是否为31天的月份
if(month==8'd1||month==8'd3||month==8'd5||month==8'd7||month==8'd8||month==8'd10||month==8'd12)
dat_flag<=8'd31;
// 判断是否为30天的月份
else if(month==8'd4||month==8'd6||month==8'd9||month==8'd11)
dat_flag<=8'd30;
// 判断是否为闰年和平年
else if(month==8'd2)
begin
if(year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
dat_flag<=28;
else dat_flag<=27;
end
计时
two_1<="C"; two_2<="l"; two_3<="o"; two_4<="c"; two_5<="k";two_12<="-";
en_sel<=1'b1;
count1<=count1+1'b1;
if(count1==32'd49_999_999)
begin
count1<=1'b0;
miao<=miao+1'b1;
if(miao==8'd59)
begin
miao<=1'b0;
fen<=fen+1'b1;
if(fen==8'd59)
begin
fen<=1'b0;
shi<=shi+1'b1;
if(shi==8'd23)
begin
shi<=1'b0;
dat<=dat+1'b1;
week<=week+1'b1;
if(week==4'b0110) week<=4'b0;
if(dat==dat_flag)
begin
dat<=8'd1;
month<=month+1'b1;
if(month==8'd12)
begin
month<=8'd1;
year<=year+1'b1;
if(year==16'd9999) year<=16'd0;//可以计1万年
end
end
end
end
end
end
end
3. 校准时的闪烁时钟
为了和其他未被调整的时间进行区分，当调整数被选中时，让他进行闪烁，所以我定义了一个闪烁时钟
//选中就闪烁
always@(posedge clk or negedge rst)//获得校准时间选中闪烁状态
begin
if(!rst)
begin
scan_flag<=1'b0;
end
else
begin
count2<=count2+1;
if(count2==32'd10_000_000)//0.2s
begin
count2<=32'b0;
scan_flag<=~scan_flag;
end
end
end
4. 调整时间
下面用年来举例，其他调整方法类似，包括调整闹钟
根据按键次数进行选择，当按键次数为3时，进入调年模式，然后进入闪烁模式，直至调整其他时间，当进入闪烁模式时，可以进行加或减的操作，key2加，key3减
4'b0010://调年
begin
case(scan_flag)
1'b0:
begin
count1<=32'b0;
one_1<=8'd20;one_2<=8'd20;one_3<=8'd20;one_4<=8'd20;
end
1'b1:
begin
count1<=32'b0;
end
endcase
if(key2)//加数
begin
year<=year+1'b1;
if(year==16'd9999)
year<=16'd0;
end
if(key3)//减数
begin
year<=year-1'b1;
if(year==16'd0)
year<=16'd9999;
end
end
三、闹钟和整点报时
对闹钟的操作，是要再定义一个时，一个分，当调整闹钟时，调整的是这个时，这个分，而不是时间中的时和分，感觉这点很重要，然后让他们进行比较的操作，如果同时相等，说明计时达到了闹钟的时间，否则没有，达到闹钟时间的时候，前两位led灯亮
对整点报时的操作就是看fen是不是为0，如果为0，后两位led灯亮，如果不是整点，led灯灭
4'b1001://设置闹铃
begin
two_1<="A"; two_2<="l"; two_3<="a"; two_4<="r"; two_5<="m";
two_7<=(alarm_shi/8'd10)+8'b00110000;
two_8<=(alarm_shi%8'd10)+8'b00110000;
two_10<=(alarm_fen/8'd10)+8'b00110000;
two_11<=(alarm_fen%8'd10)+8'b00110000;
two_12<=" ";
two_13<=" ";
two_14<=" ";
end
4'b1010://设置闹钟小时
begin
case(scan_flag)
1'b0:
begin
count1<=32'b0;
two_7<=8'h20;
two_8<=8'h20;
end
1'b1:
begin
count1<=32'b0;
two_7<=(alarm_shi/8'd10)+8'b00110000;
two_8<=(alarm_shi%8'd10)+8'b00110000;
end
endcase
if(key2)//加数
begin
alarm_shi<=alarm_shi+8'b00000001;
if(alarm_shi==8'd23)
alarm_shi<=8'b0;
end
if(key3)//减数
begin
alarm_shi<=alarm_shi-8'b00000001;
if(alarm_shi==8'b0)
alarm_shi<=23;
end
two_10<=(alarm_fen/8'd10)+8'b00110000;
two_11<=(alarm_fen%8'd10)+8'b00110000;
two_12<=" ";
two_13<=" ";
two_14<=" ";
end
4'b1011://调闹钟分钟
begin
case(scan_flag)
1'b0:
begin
count1<=32'b0;
two_10<=8'h20;
two_11<=8'h20;
end
1'b1:
begin
two_10<=(alarm_fen/8'd10)+8'b00110000;
two_11<=(alarm_fen%8'd10)+8'b00110000;
count1<=32'b0;
end
endcase
if(key2)//加数
begin
alarm_fen<=alarm_fen+8'b00000001;
if(alarm_fen==8'd23)
alarm_fen<=8'b0;
end
if(key3)//减数
begin
alarm_fen<=alarm_fen-8'b00000001;
if(alarm_fen==8'b0)
alarm_fen<=23;
end
two_7<=(alarm_shi/8'd10)+8'b00110000;
two_8<=(alarm_shi%8'd10)+8'b00110000;
two_12<=" ";
two_13<=" ";
two_14<=" ";
end
endcase
if(shi==alarm_shi && fen==alarm_fen)//闹钟响应
begin
led<=4'b0011;//前两位响应
end
// else
// begin
// led<=4'b0000;
// end
else if(fen==0)//整点报时
begin
led<=4'b1100;//后两位响应
end
else
begin
led<=4'b0000;
end
四、管脚配置
五、工程效果图
这里附上工程文件：工程文件http://download.csdn.net/download/qiaoningning/10262919