c - 修改AVR audioplayer代码播放随机轨道

Question

我已经使用 ATtiny 和 arduino 一段时间了，但在“真正的”AVR 编程方面我是一个完全的新手。我正在为我的儿子 build 一把激光枪和目标，并希望目标在被击中时随机播放愚蠢的动物声音。目标的其他功能由 Attiny85s 维护，因此我偶然发现了 Elm-Chans 代码，用于将 microSD 卡与 Attiny85 连接并通过 PWM 播放 .wav 文件。然而，代码的编写方式是使其按顺序播放 SD 卡根文件夹(或其他目录)上的文件，并响应其中一个引脚上的按钮跳至下一个。我想要它做的是当按下按钮(即击中目标)时从根目录中选择并播放随机文件。它应该只播放声音一次，如果在声音结束之前再次击中目标，最好中断已经播放的文件并播放另一个文件。我一直在努力找出代码中需要更改的内容，但后来意识到我需要从头开始学习 AVR 编程...但是这需要一些时间，在我到达那里之前我谦虚地希望你们中的任何人都可以给我一个快速解决方案并告诉我该怎么做，这样我就可以完成这个玩具。亲切的问候麦兹

/*----------------------------------------------------------------------------/
/  8-pin SD audio player R0.05d                    (C)ChaN, 2011              /
/-----------------------------------------------------------------------------/
/ This project, program codes and circuit diagrams, is opened under license
/ policy of following trems.
/
/  Copyright (C) 2010, ChaN, all right reserved.
/
/ * This project is a free software and there is NO WARRANTY.
/ * No restriction on use. You can use, modify and redistribute it for
/   personal, non-profit or commercial use UNDER YOUR RESPONSIBILITY.
/ * Redistributions of source code must retain the above copyright notice.
/
/----------------------------------------------------------------------------*/

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
#include <string.h>
#include "pff.h"
#include "xitoa.h"

#ifndef MODE
#error Wrong make file.
#endif
#if   MODE == 0 /* Single output */
FUSES = {0xE1, 0xDD, 0xFF}; /* Fuse bytes for mono: Low, High and Extended */
#else           /* Dual output */
FUSES = {0xE1, 0x7D, 0xFF}; /* Fuse bytes for stereo and mono-HR: Low, High and Extended (*HVS mode only*) */
#endif
/* This is the fuse settings of this project. The fuse data will be included
in the output hex file with program code. However some old flash programmers
cannot load the fuse bits from hex file. If it is the case, remove this line
and use these values to program the fuse bits. */


#define FCC(c1,c2,c3,c4)    (((DWORD)c4<<24)+((DWORD)c3<<16)+((WORD)c2<<8)+(BYTE)c1)    /* FourCC */

void delay_us (WORD);   /* Defined in asmfunc.S */



/*---------------------------------------------------------*/
/* Work Area                                               */
/*---------------------------------------------------------*/

volatile BYTE FifoRi, FifoWi, FifoCt;   /* FIFO controls */

BYTE Buff[256];     /* Wave output FIFO */

FATFS Fs;           /* File system object */
DIR Dir;            /* Directory object */
FILINFO Fno;        /* File information */

WORD rb;            /* Return value. Put this here to avoid avr-gcc's bug */



/*---------------------------------------------------------*/

static
DWORD load_header (void)    /* 0:Invalid format, 1:I/O error, >=1024:Number of samples */
{
    DWORD sz, f;
    BYTE b, al = 0;


    if (pf_read(Buff, 12, &rb)) return 1;   /* Load file header (12 bytes) */

    if (rb != 12 || LD_DWORD(Buff+8) != FCC('W','A','V','E')) return 0;

    for (;;) {
        wdt_reset();
        pf_read(Buff, 8, &rb);          /* Get Chunk ID and size */
        if (rb != 8) return 0;
        sz = LD_DWORD(&Buff[4]);        /* Chunk size */

        switch (LD_DWORD(&Buff[0])) {   /* Switch by chunk ID */
        case FCC('f','m','t',' ') :                 /* 'fmt ' chunk */
            if (sz & 1) sz++;                       /* Align chunk size */
            if (sz > 100 || sz < 16) return 0;      /* Check chunk size */
            pf_read(Buff, sz, &rb);                 /* Get content */
            if (rb != sz) return 0;
            if (Buff[0] != 1) return 0;             /* Check coding type (LPCM) */
            b = Buff[2];
            if (b != 1 && b != 2) return 0;         /* Check channels (1/2) */
            GPIOR0 = al = b;                        /* Save channel flag */
            b = Buff[14];
            if (b != 8 && b != 16) return 0;        /* Check resolution (8/16 bit) */
            GPIOR0 |= b;                            /* Save resolution flag */
            if (b & 16) al <<= 1;
            f = LD_DWORD(&Buff[4]);                 /* Check sampling freqency (8k-48k) */
            if (f < 8000 || f > 48000) return 4;
            OCR0A = (BYTE)(F_CPU / 8 / f) - 1;      /* Set sampling interval */
            break;

        case FCC('d','a','t','a') :     /* 'data' chunk */
            if (!al) return 0;                          /* Check if format is valid */
            if (sz < 1024 || (sz & (al - 1))) return 0; /* Check size */
            if (Fs.fptr & (al - 1)) return 0;           /* Check word alignment */
            return sz;                                  /* Start to play */

        case FCC('D','I','S','P') :     /* 'DISP' chunk */
        case FCC('L','I','S','T') :     /* 'LIST' chunk */
        case FCC('f','a','c','t') :     /* 'fact' chunk */
            if (sz & 1) sz++;               /* Align chunk size */
            pf_lseek(Fs.fptr + sz);         /* Skip this chunk */
            break;

        default :                       /* Unknown chunk */
            return 0;
        }
    }

    return 0;
}



static
void ramp (
    int dir     /* 0:Ramp-down, 1:Ramp-up */
)
{
#if MODE != 3
    BYTE v, d, n;


    if (dir) {
        v = 0; d = 1;
    } else {
        v = 128; d = (BYTE)-1;
    }

    n = 128;
    do {
        v += d;
        OCR1A = v; OCR1B = v;
        delay_us(100);
    } while (--n);
#else
    dir = dir ? 128 : 0;
    OCR1A = (BYTE)dir; OCR1B = (BYTE)dir;
#endif
}



static
FRESULT play (
    const char *dir,    /* Directory */
    const char *fn      /* File */
)
{
    DWORD sz;
    FRESULT res;
    BYTE sw;
    WORD btr;


    wdt_reset();

    xsprintf((char*)Buff, PSTR("%s/%s"), dir, fn);
    res = pf_open((char*)Buff);     /* Open sound file */
    if (res == FR_OK) {
        sz = load_header();         /* Check file format and ready to play */
        if (sz < 1024) return 255;  /* Cannot play this file */

        FifoCt = 0; FifoRi = 0; FifoWi = 0; /* Reset audio FIFO */

        if (!TCCR1) {               /* Enable audio out if not enabled */
            PLLCSR = 0b00000110;    /* Select PLL clock for TC1.ck */
            GTCCR =  0b01100000;    /* Enable OC1B as PWM */
            TCCR1 = MODE ? 0b01100001 : 0b00000001; /* Start TC1 and enable OC1A as PWM if needed */
            TCCR0A = 0b00000010;    /* Statr TC0 as interval timer at 2MHz */
            TCCR0B = 0b00000010;
            TIMSK = _BV(OCIE0A);
            ramp(1);
        }

        pf_read(0, 512 - (Fs.fptr % 512), &rb); /* Snip sector unaligned part */
        sz -= rb;
        sw = 1; /* Button status flag */
        do {    /* Data transfer loop */
            wdt_reset();

            btr = (sz > 1024) ? 1024 : (WORD)sz;/* A chunk of audio data */
            res = pf_read(0, btr, &rb); /* Forward the data into audio FIFO */
            if (rb != 1024) break;      /* Break on error or end of data */
            sz -= rb;                   /* Decrease data counter */

            sw <<= 1;                   /* Break on button down */
        } while ((PINB & 1) || ++sw != 1);
    }

    while (FifoCt) ;            /* Wait for audio FIFO empty */
    OCR1A = 128; OCR1B = 128;   /* Return output to center level */

    return res;
}



static
void delay500 (void)
{
    wdt_reset();

    TCCR0B = 0; TCCR0A = 0; /* Stop TC0 */

    if (TCCR1) {    /* Stop TC1 if enabled */
        ramp(0);
        TCCR1 = 0; GTCCR = 0;
    }

    WDTCR = _BV(WDE) | _BV(WDIE) | 0b101;   /* Set WDT to interrupt mode in timeout of 0.5s */
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);    /* Enter power down mode */
    sleep_mode();

    wdt_reset();
    WDTCR = _BV(WDE) | 0b110;               /* Set WDT to reset mode in timeout of 1s */
}


EMPTY_INTERRUPT(WDT_vect);



/*-----------------------------------------------------------------------*/
/* Main                                                                  */

int main (void)
{
    FRESULT res;
    char *dir;
    BYTE org_osc = OSCCAL;


    MCUSR = 0;
    WDTCR = _BV(WDE) | 0b110;   /* Enable WDT reset in timeout of 1s */

    PORTB = 0b101001;       /* Initialize port: - - H L H L L P */
    DDRB  = 0b111110;

    sei();

    for (;;) {
        if (pf_mount(&Fs) == FR_OK) {   /* Initialize FS */
            wdt_reset();
            Buff[0] = 0;
            if (!pf_open("osccal")) pf_read(Buff, 1, &rb);  /* Adjust frequency */
            OSCCAL = org_osc + Buff[0];

            res = pf_opendir(&Dir, dir = "wav");    /* Open sound file directory */
            if (res == FR_NO_PATH)
                res = pf_opendir(&Dir, dir = "");   /* Open root directory */

            while (res == FR_OK) {              /* Repeat in the dir */
                res = pf_readdir(&Dir, 0);          /* Rewind dir */
                while (res == FR_OK) {              /* Play all wav files in the dir */
                    wdt_reset();
                    res = pf_readdir(&Dir, &Fno);       /* Get a dir entry */
                    if (res || !Fno.fname[0]) break;    /* Break on error or end of dir */
                    if (!(Fno.fattrib & (AM_DIR|AM_HID)) && strstr(Fno.fname, ".WAV"))
                        res = play(dir, Fno.fname);     /* Play file */
                }
            }
        }
        delay500();         /* Delay 500ms in low power sleep mode */
    }
}

Answer 1

我认为您的案例需要比 AVR 黑客更多的 C 编码知识。

这里:

if (!(Fno.fattrib & (AM_DIR|AM_HID)) && strstr(Fno.fname, ".WAV"))
      res = play(dir, Fno.fname);     /* Play file */

每次找到匹配的文件时，都会调用播放函数。您想要的是将这个文件描述符添加到某种形式的可用文件容器(例如列表)中。列出所有文件后，您可能需要等待外部输入(被激光击中)，然后播放文件并将当前文件索引移动到下一个。要启用暂停和重置播放，我建议使用外部中断来处理“点击时”事件。

PS 使用 AVR 为您的 child 制作玩具？我的 +1!