Risc-V Board - Digital Clock Comprehensive Design Experiment
Experimental Manuals FPGA Tutor Risc-V

Risc-V Board Tutorial : Digital Clock Comprehensive Design Experiment- FII-PRX100 FPGA Board Experiment 6

Experiment 6 Digital Clock Comprehensive Design Experiment

1.Experiment Objective

    1. Design month, day, hour, minute, and second digital clock experiments, using 6 segment decoders
          1. 60 seconds carried to the minute
          2. 60 minutes carried to the hour
          3. 24 hours carried to the day
          4. 30 days carried to the month, and reset all
    2. Set four keys: menu, left, up, down
      1. The menu key controls the calibration function to switch between clock, date, and alarm.
      2. The left key selects which value is currently calibrated
      3. The Up and down keys add 1 and subtract 1 calibration to the data to be calibrated requires that the corresponding segment decoder is flashed.
      4. Modulate the design so that it can be reused
    3. Learn to use the module parameters
    4. Learn to use the timing analysis function of Vivado and correctly constrain the clock signal

2.Design Procedure

  1. Build new project
      1. Project name is calendar_counter
      2. Select the device 10CL040YF484CG
      3. The top-level entity is calendar_counter.bdf or calendar_counter.v (Here the Verilog file is used)
  2. Design and integrate of submodule
      1. PLL module
      2. Frequency divider
      3. Button debounce module
      4. Counting module dual_num_count.v

Design a universal 2-bit counter that uses the parameter to specify the specified count setting.

Module dual_num_count

#(parameter PAR_COUNTA=9,

parameter PAR_COUNTB=5

)

(

input i_sys_clk,

input i_ext_rst,

input i_adj_up,

input i_adj_down,

input [1:0] i_adj_sel,

input i_trig_f,

output reg o_trig_f,

output reg [3:0] o_counta,

output reg [3:0] o_countb

);

always@(posedge i_sys_clk)

if(!i_ext_rst)begin

o_counta <=0;

o_countb <=0;

o_trig_f <=1’b0;

end

else begin

o_trig_f<=1’b0;

if(i_adj_up)begin

if(!i_adj_sel[0])begin

if(o_counta==9)

o_counta<=0;

else

o_counta<=o_counta+1;

end

else if(!i_adj_sel[1])

begin

if(o_countb==9)

o_countb<=0;

else

o_countb<=o_countb+1;

end

end

else if(i_adj_down) begin

if(!i_adj_sel[0])begin

if(o_counta==0)

o_counta<=9;

else

o_counta<=o_counta-1;

end

else if(!i_adj_sel[1])begin

if(o_countb==0)

o_countb<=9;

else

o_countb<=o_countb-1;

end

end

else if(i_trig_f) begin

if((o_countb==PAR_COUNTB)&&(o_counta==PAR_COUNTA))

begin

o_counta<=4’d0;

o_countb<=0;

o_trig_f<=1’b1;

end

else begin

if(o_counta==9)begin

o_counta<=4’d0;

o_countb<=o_countb+1;

end

else begin

o_counta<=o_counta+1;

end

end

end

end

endmodule

  1. Button debounce
module pb_ve(

input sys_clk,

input sys_rst,

input ms_f,

input keyin,

output keyout

);

reg keyin_r;

reg keyout_r;

//push_button vibrating elemination

reg [1:0] ve_key_st;

reg [3:0] ve_key_count;

always@(posedge sys_clk)

keyin_r<=keyin;

always@(posedge sys_clk)

if(sys_rst) begin

keyout_r <=1’b0;

ve_key_count <=0;

ve_key_st <=0;

end

else case(ve_key_st)

0:begin

keyout_r<=1’b0;

ve_key_count <=0;

if(!keyin_r)

ve_key_st <=1;

end

1:begin

if(keyin_r)

ve_key_st <=0;

else begin

if(ve_key_count==10) begin

ve_key_st <=2;

end

else if(ms_f)

ve_key_count<=ve_key_count+1;

 

end

end

2:begin

ve_key_count <=0;

if(keyin_r)

ve_key_st <=3;

end

3:begin

if(!keyin_r)

ve_key_st <=2;

else begin

if(ve_key_count==10) begin

ve_key_st <=0;

keyout_r<=1’b1;

end

else if(ms_f)

ve_key_count<=ve_key_count+1;

end

end

default:;

endcase

assign keyout=keyout_r;

endmodule

  1. Top-level entity design
 

module calendar_counter(

 

input rst,

input left, //key4

input right,

input up,

input down,

input inclk, //c0_50Mclk

output reg [6:0] seven_sega,

outpu reg disp_pa,

output reg [5:0] scan

);

 

wire sys_clk;

wire pll_locked;

reg sys_rst;

reg ext_rst;

 

reg [7:0] us_reg;

reg [9:0] ms_reg;

reg [9:0] s_reg;

reg us_f,ms_f,s_f;

wire min_f,hr_f,day_f;

 

reg [3:0] counta;

 

wire [3:0] count_secl,count_sech;

wire [3:0] count_minl,count_minh;

wire [3:0] count_hrl,count_hrh;

 

wire [3:0] count_dayl,count_dayh;

 

reg [6:0]seven_seg_ra;

reg [7:0]disp_p_r;

 

wire left_r,right_r;

wire up_r,down_r;

 

 

always@(posedge sys_clk) begin

sys_rst<=!pll_locked;

ext_rst<=rst;

end

 

always@(posedge sys_clk)

if(sys_rst) begin

us_reg<=0;

us_f<=1’b0;

end

else begin

us_f<=1’b0;

if(us_reg==99)begin

us_reg<=0;

us_f<=1’b1;

end

else begin

us_reg<=us_reg+1;

end

 

end

 

always@(posedge sys_clk)

if(sys_rst) begin

ms_reg<=0;

ms_f<=1’b0;

end

else begin

ms_f<=1’b0;

if(us_f) begin

if(ms_reg==999)begin

ms_reg<=0;

ms_f<=1’b1;

end

else

ms_reg<=ms_reg+1;

end

end

 

always@(posedge sys_clk)

if(sys_rst) begin

s_reg<=0;

s_f<=1’b0;

end

else begin

s_f<=1’b0;

if(ms_f)begin if(s_reg==999)begin

s_reg<=0;

s_f<=1’b1;

end

else s_reg<=s_reg+1;

end

end

dual_num_count

#(.PAR_COUNTA(9),

.PAR_COUNTB(5)

)

dual_num_count_sec

(

.i_sys_clk (sys_clk),

.i_ext_rst (ext_rst),

.i_adj_up (up_r),

.i_adj_down (down_r),

.i_adj_sel (disp_p_r[1:0]),

.i_trig_f (s_f),

.o_trig_f (min_f),

.o_counta (count_secl),

.o_count (count_sech)

);

 

dual_num_count

#(.PAR_COUNTA(9),

.PAR_COUNTB(5)

)

dual_num_count_min

(

.i_sys_clk(sys_clk),

.i_ext_rst (ext_rst),

.i_adj_up (up_r),

.i_adj_down (down_r),

.i_adj_sel (disp_p_r[3:2]),

.i_trig_f (min_f),

.o_trig_f (hr_f),

.o_counta (count_minl),

.o_countb (count_minh)

);

 

dual_num_count

#(.PAR_COUNTA(3),.PAR_COUNTB(2))

dual_num_count_hr

(

.i_sys_clk (sys_clk),

.i_ext_rst (ext_rst),

.i_adj_up (up_r),

.i_adj_down (down_r),

.i_adj_sel (disp_p_r[5:4]),

.i_trig_f (hr_f),

.o_trig_f (day_f),

.o_counta (count_hrl),

.o_countb (count_hrh)

);

 

dual_num_count

#(.PAR_COUNTA(0),

.PAR_COUNTB(3)

)

dual_num_count_day

(

.i_sys_clk (sys_clk),

.i_ext_rst (ext_rst),

.i_adj_up (up_r),

.i_adj_down (down_r),

.i_adj_sel (disp_p_r[7:6]),

.i_trig_f (day_f),

.o_trig_f (),

.o_counta (count_dayl),

.o_countb (count_dayh)

);

 

always@(posedge sys_clk)

if(!ext_rst) begin

disp_p_r<=8’b1111_1110;

end

else begin

if(left_r)

disp_p_r<={disp_p_r[6:0],disp_p_r[7]};

else if(right_r)

disp_p_r<={disp_p_r[0],disp_p_r[7:1]};

end

reg [2:0] scan_st;

 

always@(posedge sys_clk)

if(!ext_rst) begin

scan<=6’b11_1111;

counta<=4’b0;

disp_pa<=1’b1;

scan_st<=0;

end

else case(scan_st)

0:begin

scan <=6’b11_1110;

counta <=count_secl;

disp_pa<=disp_p_r[0];

if(ms_f)

scan_st<=1;

end

1:begin

scan<=6’b11_1101;

counta<=count_sech;

disp_pa<=disp_p_r[1];

if(ms_f)

scan_st<=2;

end

2:begin

scan<=6’b11_1011;

counta<=count_minl;

disp_pa<=disp_p_r[2];

if(ms_f)

scan_st<=3;

end

3:begin

scan<=6’b11_0111;

counta<=count_minh;

disp_pa<=disp_p_r[3];

if(ms_f)

scan_st<=4;

end

4:begin

scan<=6’b10_1111;

counta<=count_hrl;

disp_pa<=disp_p_r[4];

if(ms_f)

scan_st<=5;

end

5:begin

scan<=6’b01_1111;

counta<=count_hrh;

disp_pa<=disp_p_r[5];

if(ms_f)

scan_st<=0;

end

default:scan_st<=0;

endcase

 

always@(*)

case(counta)

0:seven_seg_ra<=7’b100_0000;

1:seven_seg_ra<=7’b111_1001;

2:seven_seg_ra<=7’b010_0100;

3:seven_seg_ra<=7’b011_0000;

4:seven_seg_ra<=7’b001_1001;

5:seven_seg_ra<=7’b001_0010;

6:seven_seg_ra<=7’b000_0010;

7:seven_seg_ra<=7’b111_1000;

8:seven_seg_ra<=7’b000_0000;

9:seven_seg_ra<=7’b001_0000;

default:seven_seg_ra<=7’b100_0000;

endcase

always@(posedge sys_clk)

seven_sega<=seven_seg_ra;

pb_ve pb_ve_left

(

.sys_clk (sys_clk),

.sys_rst (sys_rst),

.ms_f (ms_f),

.keyin (left),

.keyout (left_r)

);

 

pb_ve pb_ve_right

(

.sys_clk (sys_clk),

.sys_rst (sys_rst),

.ms_f (ms_f),

.keyin (right),

.keyout (right_r)

);

pb_ve pb_ve_up

(

.sys_clk (sys_clk),

.sys_rst (sys_rst),

.ms_f (ms_f),

.keyin (up),

.keyout (up_r)

);

pb_ve pb_ve_down

(

.sys_clk (sys_clk),

.sys_rst (sys_rst),

.ms_f (ms_f),

.keyin (down),

.keyout (down_r)

);

 

calendar_pll calendar_pll

(

.reset (1’b0),

.inclk (inclk),

.c0 (sys_clk),

.locked (pll_locked)

);

 

endmodule

  1. Lock the Pins
Signal Name Port Description Network Label FPGA Pin
inclk System clock, 50 MHz C10_50MCLK U22
rst Reset, high by default KEY1 M4
seven_seg[0] Segment a SEG_PA K26
seven_seg[1] Segment b SEG_PB M20
seven_seg[2] Segment c SEG_PC L20
seven_seg[3] Segment d SEG_PD N21
seven_seg[4] Segment e SEG_PE N22
seven_seg[5] Segment f SEG_PF P21
seven_seg[6] Segment g SEG_PG P23
seven_seg[7] Segment h SEG_DP P24
scan[0] Segment 6 SEG_3V3_D5 T24
scan[1] Segment 5 SEG_3V3_D4 R25
scan[2] Segment 4 SEG_3V3_D3 K25
scan[3] Segment 3 SEG_3V3_D2 N18
scan[4] Segment 2 SEG_3V3_D1 R18
scan[5] Segment 1 SEG_3V3_D0 R6
left Left button KEY4 K5
right Right button KEY6 P1
up Up button KEY2 L4
down Bottom button KEY2 R7
  1. Compile
  2. Download the program to the develop board for verification
      1. Observe the test result
      2. Use the left, right keys to move the decimal point of the segment decoder
      3. Use up, down keys to calibrate time

The test result is shown in Fig 6. 1, displaying time 10:27:05

 Risc-V Board  - Digital Clock Comprehensive Design Experiment
Risc-V Board – Digital Clock Comprehensive Design Experiment

Fig 6. 1 Test result

3.Create an XDC File to Constrain the Clock

  1. Create constrain file
 Risc-V Board  - Digital Clock Comprehensive Design Experiment
Risc-V Board – Digital Clock Comprehensive Design Experiment

Fig 6. 2 Craete SDC file

XDC file is as follows:

# Create Clock

create_clock -period 20 -name inclk -waveform {0.000 10.000} [get_ports inclk]

  1. Improve the precision when using up, down to calibrate
      1. The maximum value is automatic recognized, such as in the sexagesimal decimal digit calibration time, if the value reaches 5, the next Up will make the value become 0. When the timing of Down is reduced to 0, the next Down pulse will automatically change to 5.
      2. Compile, and download the program to the develop board
      3. Program to the flash memory

Related posts

Leave a Comment