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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [sysc/] [src/] [UartSC.cpp] - Rev 131
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// ---------------------------------------------------------------------------- // SystemC Uart: implementation // This file is part of the cycle accurate model of the OpenRISC 1000 based // system-on-chip, ORPSoC, built using Verilator. // This program 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 3 of the License, or (at your // option) any later version. // This program 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 program. If not, see <http://www.gnu.org/licenses/>. // ---------------------------------------------------------------------------- // $Id: $ #include <iostream> #include <iomanip> #include <cmath> #include "UartSC.h" //#define UART_SC_DEBUG SC_HAS_PROCESS( UartSC ); //! Constructor for the Uart system C model //! @param[in] name Name of this module, passed to the parent constructor. // Todo: Probably some sort of scaler parameter UartSC::UartSC (sc_core::sc_module_name name): sc_module (name) { SC_METHOD (checkTx); dont_initialize(); sensitive << clk.pos(); //sensitive << uarttx; } // UartSC () void UartSC::initUart (int clk_freq_hz, // Presume in NS int uart_baud ) { // Calculate number of clocks per UART bit clocks_per_bit = (int)(clk_freq_hz/uart_baud); bits_received=0; #ifdef UART_SC_DEBUG printf("UartSC Initialised: Sys. clk. freq.: %d Hz, Baud: %d, cpb: %d\n", clk_freq_hz, uart_baud, clocks_per_bit); #endif } // Maybe do this with threads instead?! void UartSC::checkTx () { #ifdef UART_SC_DEBUG //printf("Uart TX activity: level is : 0x%x\n", uarttx.read()&1); #endif // Check the number of bits received if (bits_received==0) { // Check if tx is low if ((uarttx.read()&1) == 0) { // Line pulled low, begin receive of new char current_char = 0; // Start counter = 1; bits_received++; // We got the start bit #ifdef UART_SC_DEBUG cout << "UartSC checkTx: got start bit at time " << sc_time_stamp() << endl; #endif } } else if (bits_received > 0 && bits_received < 9) { // Check the counter - see if it's time to sample the line // We do an extra half-bit delay on first bit read if ( ((bits_received==1) && (counter == (clocks_per_bit + (clocks_per_bit/2)))) || ((bits_received > 1) && (counter == clocks_per_bit)) ) { //printf("UartSC checkTx: read bit %d as 0x%x at time", bits_received, uarttx.read()&1); //cout << sc_time_stamp() << endl; // Shift in the current value of the tx into our char current_char |= ((uarttx.read() & 1) << (bits_received-1)); // Reset the counter counter = 1; // Increment bit number bits_received++; } else counter++; } else if (bits_received == 9) { // Now check for stop bit 1 if (counter == clocks_per_bit) { // Check that the value is 1 - this should be the stop bit if ((uarttx.read() & 1) != 1) { printf("UART TX framing error at time\n"); cout << sc_time_stamp() << endl; // Perhaps do something else here to deal with this bits_received = 0; counter = 0; } else { // Print the char #ifdef UART_SC_DEBUG printf("Char received: 0x%2x time: ", current_char); cout << sc_time_stamp() << endl; #endif // cout'ing the char didn't work for some systems - jb 090613ol //cout << current_char; printf("%c",current_char); bits_received = 0; counter = 0; } } else counter++; } }
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