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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [verilog/] [uart_decoder.v] - Rev 426
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////////////////////////////////////////////////////////////////////// //// //// //// ORPSoC Testbench UART Decoder //// //// //// //// Description //// //// ORPSoC Testbench UART output decoder //// //// //// //// To Do: //// //// //// //// //// //// Author(s): //// //// - jb, jb@orsoc.se //// //// //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2009 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 //// //// //// ////////////////////////////////////////////////////////////////////// // Receieves and decodes 8-bit, 1 stop bit, no parity UART signals. `timescale 1ns/1ns module uart_decoder(clk, uart_tx); input clk; input uart_tx; // Default baud of 115200, period (ns) parameter uart_baudrate_period_ns = 8680; // Something to trigger the task always @(posedge clk) uart_decoder; task uart_decoder; reg [7:0] tx_byte; begin while (uart_tx !== 1'b1) @(uart_tx); // Wait for start bit while (uart_tx !== 1'b0) @(uart_tx); #(uart_baudrate_period_ns+(uart_baudrate_period_ns/2)); tx_byte[0] = uart_tx; #uart_baudrate_period_ns; tx_byte[1] = uart_tx; #uart_baudrate_period_ns; tx_byte[2] = uart_tx; #uart_baudrate_period_ns; tx_byte[3] = uart_tx; #uart_baudrate_period_ns; tx_byte[4] = uart_tx; #uart_baudrate_period_ns; tx_byte[5] = uart_tx; #uart_baudrate_period_ns; tx_byte[6] = uart_tx; #uart_baudrate_period_ns; tx_byte[7] = uart_tx; #uart_baudrate_period_ns; //Check for stop bit if (uart_tx !== 1'b1) begin // Wait for return to idle while (uart_tx !== 1'b1) @(uart_tx); end // display the char $write("%c", tx_byte); end endtask // user_uart_read_byte endmodule // uart_decoder
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