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Diffstat (limited to 'tests/iwls2005/spi/spi_clgen.v')
| -rw-r--r-- | tests/iwls2005/spi/spi_clgen.v | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/tests/iwls2005/spi/spi_clgen.v b/tests/iwls2005/spi/spi_clgen.v new file mode 100644 index 000000000..7bc4f6e5e --- /dev/null +++ b/tests/iwls2005/spi/spi_clgen.v @@ -0,0 +1,108 @@ +////////////////////////////////////////////////////////////////////// +//// //// +//// spi_clgen.v //// +//// //// +//// This file is part of the SPI IP core project //// +//// http://www.opencores.org/projects/spi/ //// +//// //// +//// Author(s): //// +//// - Simon Srot (simons@opencores.org) //// +//// //// +//// All additional information is avaliable in the Readme.txt //// +//// file. //// +//// //// +////////////////////////////////////////////////////////////////////// +//// //// +//// Copyright (C) 2002 Authors //// +//// //// +//// This source file may be used and distributed without //// +//// restriction provided that this copyright statement is not //// +//// removed from the file and that any derivative work contains //// +//// the original copyright notice and the associated disclaimer. //// +//// //// +//// This source file is free software; you can redistribute it //// +//// and/or modify it under the terms of the GNU Lesser General //// +//// Public License as published by the Free Software Foundation; //// +//// either version 2.1 of the License, or (at your option) any //// +//// later version. //// +//// //// +//// This source 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 Lesser General Public License for more //// +//// details. //// +//// //// +//// You should have received a copy of the GNU Lesser General //// +//// Public License along with this source; if not, download it //// +//// from http://www.opencores.org/lgpl.shtml //// +//// //// +////////////////////////////////////////////////////////////////////// + +`include "spi_defines.v" +`include "timescale.v" + +module spi_clgen (clk_in, rst, go, enable, last_clk, divider, clk_out, pos_edge, neg_edge); + + parameter Tp = 1; + + input clk_in; // input clock (system clock) + input rst; // reset + input enable; // clock enable + input go; // start transfer + input last_clk; // last clock + input [`SPI_DIVIDER_LEN-1:0] divider; // clock divider (output clock is divided by this value) + output clk_out; // output clock + output pos_edge; // pulse marking positive edge of clk_out + output neg_edge; // pulse marking negative edge of clk_out + + reg clk_out; + reg pos_edge; + reg neg_edge; + + reg [`SPI_DIVIDER_LEN-1:0] cnt; // clock counter + wire cnt_zero; // conter is equal to zero + wire cnt_one; // conter is equal to one + + + assign cnt_zero = cnt == {`SPI_DIVIDER_LEN{1'b0}}; + assign cnt_one = cnt == {{`SPI_DIVIDER_LEN-1{1'b0}}, 1'b1}; + + // Counter counts half period + always @(posedge clk_in or posedge rst) + begin + if(rst) + cnt <= #Tp {`SPI_DIVIDER_LEN{1'b1}}; + else + begin + if(!enable || cnt_zero) + cnt <= #Tp divider; + else + cnt <= #Tp cnt - {{`SPI_DIVIDER_LEN-1{1'b0}}, 1'b1}; + end + end + + // clk_out is asserted every other half period + always @(posedge clk_in or posedge rst) + begin + if(rst) + clk_out <= #Tp 1'b0; + else + clk_out <= #Tp (enable && cnt_zero && (!last_clk || clk_out)) ? ~clk_out : clk_out; + end + + // Pos and neg edge signals + always @(posedge clk_in or posedge rst) + begin + if(rst) + begin + pos_edge <= #Tp 1'b0; + neg_edge <= #Tp 1'b0; + end + else + begin + pos_edge <= #Tp (enable && !clk_out && cnt_one) || (!(|divider) && clk_out) || (!(|divider) && go && !enable); + neg_edge <= #Tp (enable && clk_out && cnt_one) || (!(|divider) && !clk_out && enable); + end + end +endmodule + |