pull the git change from https://github.com/dineshannayya/riscduino.git on 15th Feb 2022 with SRAM
diff --git a/verilog/rtl/lib/clk_ctl.v b/verilog/rtl/lib/clk_ctl.v
new file mode 100644
index 0000000..7e4478b
--- /dev/null
+++ b/verilog/rtl/lib/clk_ctl.v
@@ -0,0 +1,147 @@
+//////////////////////////////////////////////////////////////////////////////
+// SPDX-FileCopyrightText: 2021 , Dinesh Annayya
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileContributor: Created by Dinesh Annayya <dinesha@opencores.org>
+////////////////////////////////////////////////////////////////////////
+//// ////
+//// Tubo 8051 cores common library Module ////
+//// ////
+//// This file is part of the Turbo 8051 cores project ////
+//// https://github.com/dineshannayya/yifive_r0.git ////
+//// http://www.opencores.org/cores/turbo8051/ ////
+//// ////
+//// Description ////
+//// Turbo 8051 definitions. ////
+//// ////
+//// To Do: ////
+//// nothing ////
+//// ////
+//// Author(s): ////
+//// - Dinesh Annayya, dinesha@opencores.org ////
+//// ////
+//// Revision : ////
+//// 1.0 Mar 2, 2011,Dinesh.A ////
+//// Initial Version ////
+//// 1.1 Nov 15,2021,Dinesh A ////
+//// Bug fix in High and Low count width ////
+//// ////
+//////////////////////////////////////////////////////////////////////
+//// ////
+//// Copyright (C) 2000 Authors and OPENCORES.ORG ////
+//// ////
+//// 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 ////
+//// ////
+//////////////////////////////////////////////////////////////////////
+
+// #################################################################
+// Module: clk_ctl
+//
+// Description: Generic clock control logic , clk-out = mclk/(2+clk_div_ratio)
+//
+//
+// #################################################################
+
+
+module clk_ctl (
+ // Outputs
+ clk_o,
+ // Inputs
+ mclk,
+ reset_n,
+ clk_div_ratio
+ );
+
+//---------------------------------
+// CLOCK Default Divider value.
+// This value will be change from outside
+//---------------------------------
+parameter WD = 'h1;
+
+//---------------------------------------------
+// All the input to this block are declared here
+// --------------------------------------------
+ input mclk ;//
+ input reset_n ;// primary reset signal
+ input [WD:0] clk_div_ratio ;// primary clock divide ratio
+ // output clock = selected clock / (div_ratio+1)
+
+//---------------------------------------------
+// All the output to this block are declared here
+// --------------------------------------------
+ output clk_o ; // clock out
+
+
+
+//------------------------------------
+// Clock Divide func is done here
+//------------------------------------
+reg [WD:0] high_count ; // high level counter
+reg [WD:0] low_count ; // low level counter
+reg mclk_div ; // divided clock
+
+
+assign clk_o = mclk_div;
+
+always @ (posedge mclk or negedge reset_n)
+begin // {
+ if(reset_n == 1'b0)
+ begin
+ high_count <= 'h0;
+ low_count <= 'h0;
+ mclk_div <= 'b0;
+ end
+ else
+ begin
+ if(high_count != 0)
+ begin // {
+ high_count <= high_count - 1;
+ mclk_div <= 1'b1;
+ end // }
+ else if(low_count != 0)
+ begin // {
+ low_count <= low_count - 1;
+ mclk_div <= 1'b0;
+ end // }
+ else
+ begin // {
+ high_count <= clk_div_ratio[WD:1] + clk_div_ratio[0];
+ low_count <= clk_div_ratio[WD:1] + 1;
+ mclk_div <= ~mclk_div;
+ end // }
+ end // }
+end // }
+
+
+endmodule
+
