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TSConf_MiST/rtl/sound/jt12/jt12_eg_cnt.v
Eugene Lozovoy ba7d903e12 update JT12
2024-09-10 17:07:34 +03:00

50 lines
1.3 KiB
Verilog

/* This file is part of JT12.
JT12 is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
JT12 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with JT12. If not, see <http://www.gnu.org/licenses/>.
Author: Jose Tejada Gomez. Twitter: @topapate
Version: 1.0
Date: 29-10-2018
*/
module jt12_eg_cnt(
input rst,
input clk,
input clk_en /* synthesis direct_enable */,
input zero,
output reg [14:0] eg_cnt
);
reg [1:0] eg_cnt_base;
always @(posedge clk, posedge rst) begin : envelope_counter
if( rst ) begin
eg_cnt_base <= 2'd0;
eg_cnt <=15'd0;
end
else begin
if( zero && clk_en ) begin
// envelope counter increases every 3 output samples,
// there is one sample every 24 clock ticks
if( eg_cnt_base == 2'd2 ) begin
eg_cnt <= eg_cnt + 1'b1;
eg_cnt_base <= 2'd0;
end
else eg_cnt_base <= eg_cnt_base + 1'b1;
end
end
end
endmodule // jt12_eg_cnt