rs232.h

/*
 * Simple wrapper for writing to a RS232 port. This file is part of the
 * DOSMid project.
 *
 * Copyright (c) 2015, Mateusz Viste
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef RS232_H_SENTINEL
#define RS232_H_SENTINEL

/* get the I/O port for COMx (1..4) */
unsigned short rs232_getport(int x);

/* check if the COM port is ready for write. loops for some time waiting.
 * returns 0 if port seems ready eventually, non-zero otherwise. can be used
 * to verify the rs232 presence */
int rs232_check(unsigned short port);

/* write a byte to the COM port at 'port'. this function will block if the
 * UART is not ready to transmit yet. */
void rs232_write(unsigned short port, int data);

/* read a byte from COM port at 'port'. returns the read byte, or -1 if
 * nothing was available to read. */
int rs232_read(unsigned short port);

#endif