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Diffstat (limited to 'rtl/clkmgr_reset_gen.v')
| -rw-r--r-- | rtl/clkmgr_reset_gen.v | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/rtl/clkmgr_reset_gen.v b/rtl/clkmgr_reset_gen.v new file mode 100644 index 0000000..9cc4401 --- /dev/null +++ b/rtl/clkmgr_reset_gen.v @@ -0,0 +1,69 @@ +//====================================================================== +// +// clkmgr_reset_gen.v +// ------------------ +// System reset generator. +// +// +// Author: Pavel Shatov +// Copyright (c) 2019, NORDUnet A/S All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions +// are met: +// - Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// +// - 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. +// +// - Neither the name of the NORDUnet 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 clkmgr_reset_gen +( + input clk_in, + input locked_in, + output reset_n_out +); + + // + // Parameter + // + parameter integer SHREG_WIDTH = 16; + + // + // Shift Register + // + (* SHREG_EXTRACT="NO" *) + (* EQUIVALENT_REGISTER_REMOVAL="NO" *) + reg [SHREG_WIDTH-1:0] sys_rst_shreg = {SHREG_WIDTH{1'b0}}; + + always @(posedge clk_in or negedge locked_in) + // + if (!locked_in) sys_rst_shreg <= {SHREG_WIDTH{1'b0}}; + else sys_rst_shreg <= {sys_rst_shreg[SHREG_WIDTH-2:0], 1'b1}; + + assign reset_n_out = sys_rst_shreg[SHREG_WIDTH-1]; + +endmodule + +//====================================================================== +// EOF clkmgr_reset_gen.v +//====================================================================== |