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[/] [openrisc/] [trunk/] [orpsocv2/] [bench/] [sysc/] [src/] [UartSC.cpp] - Rev 675
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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 "UartSC.h" //#define UART_SC_DEBUG // Keep disabled for now, to stop any portability problems cropping up. //#define UART_SC_STDIN_ENABLE #ifdef UART_SC_STDIN_ENABLE #include <termios.h> #endif 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 uart): sc_module(uart) { #ifdef UART_SC_STDIN_ENABLE SC_THREAD(driveRx); #endif SC_THREAD(checkTx); dont_initialize(); sensitive << uarttx; } // UartSC () void UartSC::initUart(int uart_baud) { // Calculate number of ns per UART bit ns_per_bit = (int) ((long long)1000000000/(long long)uart_baud); bits_received = 0; // Init state of RX rx_state = 0; // Set input, ORPSoC's RX, line to high uartrx.write(true); #ifdef UART_SC_DEBUG printf ("UartSC Initialised: Baud: %d, ns per bit: %d\n", uart_baud, ns_per_bit); #endif } // Some C from // http://cc.byexamples.com/2007/04/08/non-blocking-user-input-in-loop-without-ncurses/ // int UartSC::kbhit() { #ifdef UART_SC_STDIN_ENABLE struct timeval tv; fd_set fds; tv.tv_sec = 0; tv.tv_usec = 0; FD_ZERO(&fds); FD_SET(STDIN_FILENO, &fds); //STDIN_FILENO is 0 select(STDIN_FILENO+1, &fds, NULL, NULL, &tv); return FD_ISSET(STDIN_FILENO, &fds); #else return 0; #endif } #define NB_ENABLE 1 #define NB_DISABLE 0 // The following is apparently VERY Linux-centric. Maybe a ncurses version could // be handy if this gets used on various platforms. void UartSC::nonblock(int state) { #ifdef UART_SC_STDIN_ENABLE struct termios ttystate; //get the terminal state tcgetattr(STDIN_FILENO, &ttystate); if (state==NB_ENABLE) { //turn off canonical mode ttystate.c_lflag &= ~ICANON; //minimum of number input read. ttystate.c_cc[VMIN] = 1; } else if (state==NB_DISABLE) { //turn on canonical mode ttystate.c_lflag |= ICANON; } //set the terminal attributes. tcsetattr(STDIN_FILENO, TCSANOW, &ttystate); #endif } void UartSC::driveRx() { static char c; UartSC::nonblock(NB_ENABLE); while(1) { if (rx_state == 0) // Waiting for a character input from user { // Do we have a character on input? //c=cin.peek(); if (kbhit()) { c = fgetc(stdin); #ifdef UART_SC_DEBUG cout << "UartSC::driveRX got " << c << endl; #endif rx_state++; } wait(1000000, SC_NS); } else if (rx_state == 1) { #ifdef UART_SC_DEBUG cout << "UartSC::driveRX start-bit " << c << endl; #endif // Start bit - low uartrx.write(false); rx_state++; // Wait a bit wait(ns_per_bit, SC_NS); } else if (rx_state > 1 && rx_state < 10) { #ifdef UART_SC_DEBUG cout << "UartSC::driveRX bit " << rx_state-2 << " " << (c & (1 << rx_state-2)) << endl; #endif if (c & (1 << rx_state-2)) uartrx.write(true); else uartrx.write(false); rx_state++; // Wait a bit wait(ns_per_bit, SC_NS); } else if (rx_state == 10) { #ifdef UART_SC_DEBUG cout << "UartSC::driveRX stop bit" << endl; #endif rx_state = 0; // Stop bit uartrx.write(true); // Wait a bit wait(ns_per_bit + (ns_per_bit/2), SC_NS); } } } // Maybe do this with threads instead?! void UartSC::checkTx() { while(1){ // 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; //counter = 1; bits_received++; // We got the start bit // Now wait until next bit wait(ns_per_bit, SC_NS); #ifdef UART_SC_DEBUG cout << "UartSC checkTx: got start bit at time " << sc_time_stamp() << endl; #endif } else // Nothing yet - keep waiting wait(ns_per_bit/2, SC_NS); } else if (bits_received > 0 && bits_received < 9) { current_char |= ((uarttx.read() & 1) << (bits_received - 1)); // Increment bit number bits_received++; // Wait for next bit wait(ns_per_bit, SC_NS); } else if (bits_received == 9) { // Now check for stop bit 1 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; } 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. //cout << current_char; printf("%c", current_char); bits_received = 0; } } } }
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