blob: 4581bbc564de8db9233106901ff40d1f3861afe3 [file] [log] [blame]
`default_nettype none
/*
Verilog code for playing a RTTL ringtone on a Piezo Speaker
Copyright 2022 Milosch Meriac <milosch@meriac.com>
Location: https://github.com/meriac/tt02-play-tune/
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
module meriac_tt02_play_tune #( parameter MAX_COUNT = 100 ) (
input [7:0] io_in,
output [7:0] io_out
);
wire clk = io_in[0];
wire reset = io_in[1];
wire [10:0] db_entry;
reg [6:0] note_address;
reg [10:0] ticks;
reg [6:0] freq, counter;
reg speaker;
assign io_out[0] = speaker;
assign io_out[1] = ~speaker;
always @(posedge clk) begin
// if reset, set note_address to 0
if (reset) begin
note_address <= 0;
ticks <= 0;
freq <= 0;
counter <= 0;
speaker <= 0;
end else begin
if (!ticks) begin
if (note_address<MAX_COUNT) begin
note_address <= note_address + 1'b1;
end else begin
note_address <= 0;
end
end
// tone frequency divider
if (counter>0) begin
counter <= counter - 1'b1;
speaker <= counter >= (freq/2);
end else begin
counter <= freq;
speaker <= 1'b0;
end
end
end
always @(negedge clk) begin
if (!reset) begin
if (ticks>0) begin
ticks <= ticks - 1'b1;
end else begin
// update per-note delay
ticks[10:7] <= db_entry[3:0];
ticks[6:0] <= 0;
// reset tone generator
counter <= db_entry[10:4];
freq <= db_entry[10:4];
end
end
end
// instantiate tune database
meriac_tune_db meriac_tune_db(.address(note_address), .db_entry(db_entry));
endmodule