数码管动态扫描显示-编程知识

摸鱼记录 Day_16 (ﾟOﾟ)

review

前边已经学习了：

串口接收：Vivado 串口接收优化-CSDN博客

1. 今日摸鱼任务

串口接收数据

并用数码管显示 (ﾟOﾟ)

小梅哥视频：

17A 数码管段码显示与动态扫描原理_哔哩哔哩_bilibili

17B 数码管动态扫描显示数字逻辑建模_哔哩哔哩_bilibili

17C 数码管动态扫描显示的Verilog实现_哔哩哔哩_bilibili

17D 使能时钟和门控时钟的原理与差异_哔哩哔哩_bilibili

//虽然看起来很多，但是不会很难滴 (ﾟOﾟ)

2. 数码管显示原理

ACZ702 EDA 扩展板上板载的是共阳数码管。同时为了显示数字或字符，必须对数字或字符进行编码译码。

先不考虑小数点也就是简化为 7 段数码管，其编码译码格式如下表所示：

段式数码管工作方式有两种：静态显示方式和动态显示方式。

静态显示：每个数码管的段选必须接一个 8 位数据线来保持显示的字形码。当送入一次字形码后，显示字形可一直保持，直到送入新字形码为止。

这种方法由于每个数码管均需要独立的数据线，硬件电路比较复杂，成本较高，很少使用。

动态显示：将所有位数码管的段选线并联在一起，由位选线控制是哪一位数码管有效。选亮数码管采用动态扫描显示。所谓动态扫描显示即轮流向各位数码管送出字形码和相应的位选，利用发光管的余辉和人眼视觉暂留作用，使人的感觉好像各位数码管同时都在显示。

电路结构如下所示，这样 3 个数码管接在一起就比静态的少了 7*2 个 I/O 。

sel拉高选中

3. 时钟分频:门控时钟与使能时钟

门控时钟：

使用计数器和逻辑门翻转产生

reg [14:0]div_clk;
always@(posedge clk or negedge reset_n)
if(!reset_n)
div_clk <= 1'b0;
else if(div_clk == 24999)
div_clk <= 1'b0;
else
div_clk <= div_clk + 1'b1;

always@(posedge clk or negedge reset_n)
if(!reset_n)
clk_1 <= 1'b0;
else if(div_clk == 24999)
clk_1 <= ~clk_1;

使能时钟：

用到计数器，但是不会用到反相器，生成的信号也不会直接用于其他电路的触发

reg [14:0]div_clk;
always@(posedge clk or negedge reset_n)
if(!reset_n)
div_clk <= 1'b0;
else if(div_clk == 24999)
div_clk <= 1'b0;
else
div_clk <= div_clk + 1'b1;

always@(posedge clk or negedge reset_n)
if(!reset_n)
disp_en <= 1'b0;
else if(div_clk == 24999)
disp_en <= 1'b1;
else
disp_en <= 1'b0;

对比：

门控时钟的时钟延迟不稳定，且延迟比较大

使得时钟的波形变差

驱动能力差

小结：设计中一般情况下使用使能时钟的时钟分频方式

4. hex_8

4.1 design sources

hex_8

module hex_8(input clk,
input reset_n,
input [31:0]disp_data,
output reg [7:0]sel,
output reg [7:0]seg
);

//[31:0]disp_data 16hex 4*8
//[7:0]sel 位选信号
//[7:0]seg 段选信号

// 1kHz分频时钟
reg [14:0]div_clk;
always@(posedge clk or negedge reset_n)
if(!reset_n)
div_clk <= 1'b0;
else if(div_clk == 24999)
div_clk <= 1'b0;
else
div_clk <= div_clk + 1'b1;
reg disp_en;
always@(posedge clk or negedge reset_n)
if(!reset_n)
disp_en <= 1'b0;
else if(div_clk == 24999)
disp_en <= 1'b1;
else
disp_en <= 1'b0;

// 位选sel
reg[2:0]sel_num;
always@(posedge clk or negedge reset_n)
if(!reset_n)
sel_num <= 3'b000;
else if(disp_en)
sel_num <= sel_num + 1'b1;
//sel_num =3’b111; +1'b1 3'b000;
always@(posedge clk or negedge reset_n)
if(!reset_n)
sel <= 8'b0000_0000;
else case(sel_num)
0:sel <= 8'b0000_0001;
1:sel <= 8'b0000_0010;
2:sel <= 8'b0000_0100;
3:sel <= 8'b0000_1000;
4:sel <= 8'b0001_0000;
5:sel <= 8'b0010_0000;
6:sel <= 8'b0100_0000;
7:sel <= 8'b1000_0000;
endcase

// 段选seg [31:0]disp_data 16hex 4*8
reg [3:0] dis_tmp;
always@(posedge clk )
case(sel_num) //高位放前面
0:dis_tmp <= disp_data[31:28];
1:dis_tmp <= disp_data[27:24];
2:dis_tmp <= disp_data[23:20];
3:dis_tmp <= disp_data[19:16];
4:dis_tmp <= disp_data[15:12];
5:dis_tmp <= disp_data[11:8];
6:dis_tmp <= disp_data[7:4];
7:dis_tmp <= disp_data[3:0];
endcase

always@(posedge clk)
case(dis_tmp)
0:seg <= 8'hc0;
1:seg <= 8'hf9;
2:seg <= 8'ha4;
3:seg <= 8'hb0;
4:seg <= 8'h99;
5:seg <= 8'h92;
6:seg <= 8'h82;
7:seg <= 8'hf8;
8:seg <= 8'h80;
9:seg <= 8'h90;
4'ha:seg <= 8'h88;
4'hb:seg <= 8'h83;
4'hc:seg <= 8'hc6;
4'hd:seg <= 8'ha1;
4'he:seg <= 8'h86;
4'hf:seg <= 8'h8e;
endcase

endmodule

4.2 hex_8_tb

`timescale 1ns / 1ns
module hex_8_tb( );
reg clk , reset_n;
reg [31:0]disp_data;
wire[7:0]sel;
wire[7:0]seg;
hex_8 hex_8_(. clk(clk),
. reset_n(reset_n),
. disp_data(disp_data),
. sel(sel),
. seg(seg) );

initial clk = 1 ;
always#10 clk = ~clk;

initial
begin
reset_n = 0 ;
#201;
reset_n = 1 ;
disp_data = 32'h01234567;
#10000000;
disp_data = 32'h89abcdef;
#10000000;
$stop;
end

endmodule

红色框框内输入数据发生了改变，但是很快就会闪过去

所以没有像串口发送添加一个存储数据让其保持一个运行周期

Vivado 串口通信(UART)------串口发送-CSDN博客

5. 串口接收 + 数码管动态显示

5.1 design sources

module uart_rx(input clk ,
input reset_n ,
input uart_rx ,
output reg [7:0]rx_data,
output reg rx_done );
//默认使用波特率BAUD 9600 时钟频率 CLK_FREQ 50MHz
// parameter start_bit = 0 ;
// parameter stop_bit = 1 ;
parameter BAUD = 9600;
parameter CLK_FREQ = 50_000_000;
parameter bps_c = CLK_FREQ / BAUD ;
reg rx_en ;
reg[3:0] rx_flag;
// bps
reg [30:0] counter_bps ;
always@(posedge clk or negedge reset_n)
if(! reset_n)
counter_bps <= 0 ;
else if (rx_en)
if(counter_bps == bps_c - 1)
counter_bps <= 0 ;
else
counter_bps <= counter_bps + 1'b1 ;
else
counter_bps <= 0 ;
reg dff_rx_0 , dff_rx_1 ;
reg r_uart_rx;
wire neg_rx_go ;
always@(posedge clk )
dff_rx_0 <= uart_rx ;
always@(posedge clk )
dff_rx_1 <= dff_rx_0 ;
always@(posedge clk )
r_uart_rx <= dff_rx_1 ;

assign neg_rx_go = (dff_rx_1 == 0)&&(r_uart_rx == 1);

// rx_en
always@(posedge clk or negedge reset_n)
if(! reset_n)
rx_en <= 0 ;
else if(neg_rx_go)
rx_en <= 1 ;
else if((rx_flag==9)&&(counter_bps == bps_c / 2))
rx_en <= 0 ;
else if((rx_flag==0)&&(counter_bps == bps_c/2 )&&(dff_rx_1==1))
rx_en <= 0 ;

// rx_flag
always@(posedge clk or negedge reset_n)
if(!reset_n) rx_flag <= 4'b0000 ;
else if((rx_flag == 9)&&(counter_bps == bps_c /2)) rx_flag <= 4'b0000 ;
else if(counter_bps == bps_c - 1) rx_flag <= rx_flag + 1'b1 ;

// [7:0]r_rx_data
reg [7:0] r_rx_data;
always@(posedge clk )
if(!rx_en) r_rx_data <= r_rx_data;
else if(counter_bps == bps_c / 2)
begin
case(rx_flag)
1 : r_rx_data[0] <= dff_rx_1;
2 : r_rx_data[1] <= dff_rx_1;
3 : r_rx_data[2] <= dff_rx_1;
4 : r_rx_data[3] <= dff_rx_1;
5 : r_rx_data[4] <= dff_rx_1;
6 : r_rx_data[5] <= dff_rx_1;
7 : r_rx_data[6] <= dff_rx_1;
8 : r_rx_data[7] <= dff_rx_1;
default : r_rx_data <= r_rx_data;
endcase

end
// rx_done
always@(posedge clk)
rx_done <= (rx_flag==9)&&(counter_bps == bps_c /2);
// rx_data ;
always@(posedge clk)
if(rx_done) rx_data <= r_rx_data;
endmodule

rx_hex8

module rx_hex8(input clk,
input reset_n,
input uart_rx ,
output [7:0]sel,
output [7:0]seg
);

reg [1:0] rx_done_flag;
reg [31:0]disp_data;
wire [7:0] rx_data;
wire rx_done;
uart_rx uart_rx_(. clk(clk) , . reset_n(reset_n) ,.uart_rx(uart_rx) ,
. rx_data(rx_data), . rx_done(rx_done) );
always@(posedge clk or negedge reset_n)
if(! reset_n)
rx_done_flag <= 2'b11 ;
else if(rx_done)
rx_done_flag <= rx_done_flag + 1'b1 ;
always@(posedge clk or negedge reset_n)
if(! reset_n)
disp_data <= 8'h0000_0000 ;
else
case(rx_done_flag)
0:begin disp_data <= disp_data; disp_data[7:0] <= rx_data;end
1:begin disp_data <= disp_data; disp_data[15:8] <= rx_data;end
2:begin disp_data <= disp_data; disp_data[23:16] <= rx_data;end
3:begin disp_data <= disp_data; disp_data[31:24] <= rx_data;end
endcase

hex_8 hex_8_(. clk(clk),
. reset_n(reset_n),
. disp_data(disp_data),
.sel(sel),
.seg(seg)
);
endmodule

5.2 rx_hex8_tb

`timescale 1ns / 1ns
module hex_8_tb( );
reg clk , reset_n , uart_rx_;
wire[7:0]sel;
wire[7:0]seg;
rx_hex8 rx_hex8_(. clk(clk),
. reset_n(reset_n),
. uart_rx(uart_rx_),
. sel(sel),
. seg(seg)
);
initial clk = 1 ;
always#10 clk = ~clk;

initial
begin
reset_n = 0 ;
#201;
reset_n = 1 ;
uart_rx_ = 1 ;#(5208*20);
//0 f
uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

//9 6
uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

//4 5
uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);uart_rx_ = 1 ;

#(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

// 3 c
uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

        uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

//0 f
uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

        uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);


uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);

uart_rx_ = 0 ; #(5208*20);uart_rx_ = 0 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);

uart_rx_ = 1 ; #(5208*20);uart_rx_ = 1 ; #(5208*20);
uart_rx_ = 1 ; #(5208*20);
# 10000;
$stop;
end

endmodule