serial.c

编译后直接运行的ＭＰ３播放器全部Ｃ语言源代码 一个包含FAT文件系统、系统引导 Boot、FLASH Driver等内容的

/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id: serial.c,v 1.11 2004/03/02 11:32:59 linusnielsen Exp $
 *
 * Copyright (C) 2002 by Alan Korr & Nick Robinson
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <stdlib.h>
#include "button.h"
#include "config.h"
#include "sh7034.h"
#include "system.h"
#include "kernel.h"
#include "backlight.h"
#include "adc.h"
#include "lcd.h"
#include "serial.h"

/* Received byte identifiers */
#define PLAY  0xC1
#define STOP  0xC2
#define PREV  0xC4
#define NEXT  0xC8
#define VOLUP 0xD0
#define VOLDN 0xE0

#ifdef SCREENDUMP
#define SCRDMP 0xF0

static void screen_dump(void);
#endif

void serial_setup (void) 
{
    /* Set PB10 function to serial Rx */
    PBCR1 = (PBCR1 & 0xffcf) | 0x0020;
    
    SMR1 = 0x00;
    SCR1 = 0;
    BRR1 = (FREQ/(32*9600))-1;
    SSR1 &= 0; /* The status bits must be read before they are cleared,
                  so we do an AND operation */

    /* Let the hardware settle. The serial port needs to wait "at least
       the interval required to transmit or receive one bit" before it
       can be used. */
    sleep(1);

    SCR1 = 0x10; /* Enable the receiver, no interrupt */
}

/* This function returns the received remote control code only if it is
   received without errors before or after the reception.
   It therefore returns the received code on the second call after the
   code has been received. */
int remote_control_rx(void)
{
    static int last_valid_button = BUTTON_NONE;
    static int last_was_error = false;
    int btn;
    int ret = BUTTON_NONE;
    
    /* Errors? Just clear'em. The receiver stops if we don't */
    if(SSR1 & (SCI_ORER | SCI_FER | SCI_PER)) {
        SSR1 &= ~(SCI_ORER | SCI_FER | SCI_PER);
        last_valid_button = BUTTON_NONE;
        last_was_error = true;
        return BUTTON_NONE;
    }

    if(SSR1 & SCI_RDRF) {
        /* Read byte and clear the Rx Full bit */
        btn = RDR1;
        SSR1 &= ~SCI_RDRF;

        if(last_was_error)
        {
            last_valid_button = BUTTON_NONE;
            ret = BUTTON_NONE;
        }
        else
        {
#ifndef HAVE_NEO_KEYPAD /* This needs to be fixed for Neo */
            switch (btn)
            {
                case STOP:
                    last_valid_button = BUTTON_RC_STOP;
                    break;
                    
                case PLAY:
                    last_valid_button = BUTTON_RC_PLAY;
                    break;
                    
                case VOLUP:
                    last_valid_button = BUTTON_RC_VOL_UP;
                    break;
                    
                case VOLDN:
                    last_valid_button = BUTTON_RC_VOL_DOWN;
                    break;
                    
                case PREV:
                    last_valid_button = BUTTON_RC_LEFT;
                    break;
                    
                case NEXT:
                    last_valid_button = BUTTON_RC_RIGHT;
                    break;
                    
#ifdef SCREENDUMP
                case SCRDMP:
                    screen_dump();
                    break;
#endif
                default:
                    last_valid_button = BUTTON_NONE;
                    break;
            }
#endif
        }
    }
    else
    {
        /* This means that a valid remote control character was received
           the last time we were called, with no receiver errors either before
           or after. Then we can assume that there really is a remote control
           attached, and return the button code. */
        ret = last_valid_button;
        last_valid_button = BUTTON_NONE;
    }
    
    last_was_error = false;

    return ret;
}

#ifdef SCREENDUMP
static void serial_enable_tx(void)
{
    SCR1 |= 0x20;
}

static void serial_tx(unsigned char ch)
{
    while (!(SSR1 & SCI_TDRE))
    {
        ;
    }
    
    /*
     * Write data into TDR and clear TDRE
     */
    TDR1 = ch;
    SSR1 &= ~SCI_TDRE;
}

static void screen_dump(void)
{
    int x, y;
    int level;

    serial_enable_tx();

    level = set_irq_level(HIGHEST_IRQ_LEVEL);
    for(y = 0;y < LCD_HEIGHT/8;y++)
    {
        for(x = 0;x < LCD_WIDTH;x++)
        {
            serial_tx(lcd_framebuffer[y][x]);
        }
    }
    set_irq_level(level);
}

#endif