| module top(input clk_pin, input btn_pin, output [7:0] led_pin); |
| |
| wire clk; |
| wire [7:0] led; |
| wire btn; |
| |
| (* LOC="A10" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("INPUT")) clk_buf (.B(clk_pin), .O(clk)); |
| |
| // Pressing and holding SW4 will trigger led array fading |
| (* LOC="P4" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("INPUT")) btn_buf (.B(btn_pin), .O(btn)); |
| |
| (* LOC="B17" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_0 (.B(led_pin[0]), .I(!led[0])); |
| (* LOC="A17" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_1 (.B(led_pin[1]), .I(!led[1])); |
| (* LOC="C17" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_2 (.B(led_pin[2]), .I(!led[2])); |
| (* LOC="B18" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_3 (.B(led_pin[3]), .I(!led[3])); |
| |
| (* LOC="A18" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_4 (.B(led_pin[4]), .I(!led[4])); |
| (* LOC="B19" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_5 (.B(led_pin[5]), .I(!led[5])); |
| (* LOC="A12" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_6 (.B(led_pin[6]), .I(!led[6])); |
| (* LOC="A13" *) (* IO_TYPE="LVCMOS33" *) |
| TRELLIS_IO #(.DIR("OUTPUT")) led_buf_7 (.B(led_pin[7]), .I(!led[7])); |
| |
| |
| |
| localparam ctr_width = 24; |
| localparam ctr_max = 2**ctr_width - 1; |
| reg [ctr_width-1:0] ctr = 0; |
| reg [9:0] pwm_ctr = 0; |
| reg dir = 0; |
| |
| always@(posedge clk) begin |
| ctr <= btn ? ctr : (dir ? ctr - 1'b1 : ctr + 1'b1); |
| if (ctr[ctr_width-1 : ctr_width-3] == 0 && dir == 1) |
| dir <= 1'b0; |
| else if (ctr[ctr_width-1 : ctr_width-3] == 7 && dir == 0) |
| dir <= 1'b1; |
| pwm_ctr <= pwm_ctr + 1'b1; |
| end |
| |
| reg [9:0] brightness [0:7]; |
| localparam bright_max = 2**10 - 1; |
| reg [7:0] led_reg; |
| |
| genvar i; |
| generate |
| for (i = 0; i < 8; i=i+1) begin |
| always @ (posedge clk) begin |
| if (ctr[ctr_width-1 : ctr_width-3] == i) |
| brightness[i] <= bright_max; |
| else if (ctr[ctr_width-1 : ctr_width-3] == (i - 1)) |
| brightness[i] <= ctr[ctr_width-4:ctr_width-13]; |
| else if (ctr[ctr_width-1 : ctr_width-3] == (i + 1)) |
| brightness[i] <= bright_max - ctr[ctr_width-4:ctr_width-13]; |
| else |
| brightness[i] <= 0; |
| led_reg[i] <= pwm_ctr < brightness[i]; |
| end |
| end |
| endgenerate |
| |
| assign led = led_reg; |
| endmodule |