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