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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [libgloss/] [or32/] [uart.c] - Rev 218
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/* uart.c. UART support functions Copyright (C) 2004, Jacob Bower Copyright (C) 2010, Embecosm Limited <info@embecosm.com> Contributor Jeremy Bennett <jeremy.bennett@embecosm.com> This file is part of Newlib. The original work by Jacob Bower is provided as-is without any kind of warranty. Use it at your own risk! All subsequent work is bound by version 3 of the GPL as follows. This program is free software; you can redistribute it and/or modify it under the terms of the GNU 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http:#www.gnu.org/licenses/>. */ /* -------------------------------------------------------------------------- */ /* This program is commented throughout in a fashion suitable for processing with Doxygen. */ /* -------------------------------------------------------------------------- */ #include "or1ksim-board.h" #include "uart.h" /*! Macro to access a UART register */ #define UREG8(reg) REG8 (UART_BASE + reg) /*! Macro to check if transmit and transmit holding registers are both empty. */ #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE) /*! Macro to wait until a char has been transmitted */ #define WAIT_FOR_XMITR \ do \ { \ lsr = UREG8 (UART_LSR); \ } \ while ((lsr & BOTH_EMPTY) != BOTH_EMPTY) /*! Macro to wait until a char can be transmitted */ #define WAIT_FOR_THRE \ do \ { \ lsr = UREG8 (UART_LSR); \ } \ while ((lsr & UART_LSR_THRE) != UART_LSR_THRE) /* Macro to see if a character has been received */ #define CHECK_FOR_CHAR (UREG8 (UART_LSR) & UART_LSR_DR) /* Macro to wait until a character is received */ #define WAIT_FOR_CHAR \ do { \ lsr = UREG8 (UART_LSR); \ } while ((lsr & UART_LSR_DR) != UART_LSR_DR) /* -------------------------------------------------------------------------- */ /*!Initialize the UART */ /* -------------------------------------------------------------------------- */ void _uart_init () { int divisor; /* Reset receiver and transmiter */ UREG8 (UART_FCR) = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT | UART_FCR_TRIGGER_14; /* Disable all interrupts */ UREG8 (UART_IER) = 0x00; /* Set 8 bit char, 1 stop bit, no parity */ UREG8 (UART_LCR) = UART_LCR_WLEN8 & ~(UART_LCR_STOP | UART_LCR_PARITY); /* Set baud rate */ divisor = IN_CLK / (16 * UART_BAUD_RATE); UREG8 (UART_LCR) |= UART_LCR_DLAB; UREG8 (UART_DLL) = divisor & 0x000000ff; UREG8 (UART_DLM) = (divisor >> 8) & 0x000000ff; UREG8 (UART_LCR) &= ~(UART_LCR_DLAB); } /* _uart_init () */ /* -------------------------------------------------------------------------- */ /*!Put a character out on the UART @param[in] c The character to output */ /* -------------------------------------------------------------------------- */ void _uart_putc (char c) { unsigned char lsr; /* Wait until we are free to transmit */ WAIT_FOR_THRE; /* Put the character to be transmitted and wait until it has gone. */ UREG8 (UART_TX) = c; WAIT_FOR_XMITR; } /* _uart_putc () */ /* -------------------------------------------------------------------------- */ /*!Get a character from the UART @reurn The character read. */ /* -------------------------------------------------------------------------- */ char _uart_getc () { unsigned char lsr; char c; /* Wait until a char is available, then get it. */ WAIT_FOR_CHAR; return UREG8 (UART_RX); } /* _uart_getc () */
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