sa

module bomba (
	input clk,
	input rst,
	input sw0,
	output [6:0] disp0
);

reg[6:0] disp0_reg,disp0_next;
integer tick_reg,tick_next;
integer crta_reg,crta_next;

localparam tus = 50_000_000;

always @(posedge clk or posedge rst)
begin
	if(rst == 1)
	begin
		disp0_reg <= 7'b1111111;
		tick_reg <= 10*tus;
		crta_reg <= 0;
	end
	else
	begin
		disp0_reg <= disp0_next;
		tick_reg <= tick_next;
		crta_reg <= crta_next;
	end
end

always @(*)
begin
	tick_next = tick_reg;
	if((sw0 == 1) || (tick_reg < 10*tus && tick_reg > 0))
	begin
		tick_next = tick_reg - 1;
	end
end

always @(*)
begin
	crta_next = crta_reg;
	if(~(tick_reg>0))
	begin
		crta_next = (crta_reg + 1) % tus;
	end
end

always @(*)
begin
	disp0_next = disp0_reg;
	if(tick_reg == 10*tus)
	begin
		disp0_next = 7'b1111111;
	end
	else if(tick_reg > 9*tus)
	begin
		disp0_next = cifra(9);
	end
	else if(tick_reg > 8*tus)
	begin
		disp0_next = cifra(8);
	end
	else if(tick_reg > 7*tus)
	begin
		disp0_next = cifra(7);
	end
	else if(tick_reg > 6*tus)
	begin
		disp0_next = cifra(6);
	end
	else if(tick_reg > 5*tus)
	begin
		disp0_next = cifra(5);
	end
	else if(tick_reg > 4*tus)
	begin
		disp0_next = cifra(4);
	end
	else if(tick_reg > 3*tus)
	begin
		disp0_next = cifra(3);
	end
	else if(tick_reg > 2*tus)
	begin
		disp0_next = cifra(2);
	end
	else if(tick_reg > tus)
	begin
		disp0_next = cifra(1);
	end
	else  if(tick_reg > 0)
	begin
		disp0_next = cifra(0);
	end
	else
	begin
		if(crta_reg < tus/2)
		begin
			disp0_next = 7'b0111111;
		end
		else
		begin
			disp0_next = 7'b1111111;
		end
	end
end

function[6:0] cifra(input integer broj);
begin
	case(broj)
		0: cifra = 7'b1000000;
		1: cifra = 7'b1111001;
		2: cifra = 7'b0100100;
		3: cifra = 7'b0110000;
		4: cifra = 7'b0011001;
		5: cifra = 7'b0010010;
		6: cifra = 7'b0000010;
		7: cifra = 7'b1111000;
		8: cifra = 7'b0000000;
		9: cifra = 7'b0010000;
		default: cifra = 7'b1111111;
	endcase
end
endfunction

assign disp0 = disp0_reg;

endmodule