blob: 5d487124cf9403346d9af2628dbc48494f815887 [file] [log] [blame]
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