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AdaFruit Wave Shield WaveHC dap (voir la source)
Version du 13 mars 2012 à 12:39
, 13 mars 2012 à 12:39aucun résumé de modification
// Print out all of the files in all the directories.
// Print out all of the files in all the directories.
lsR(root);
lsR(root);
}
</nowiki>
== Looking for files in a directory ==
OK now that you've initialized the card, we perform a recursive list of all files found. This is useful for debugging and ALSO shows how you can navigate the file system
To start, pass a directory object (like '''root''') to '''lsR()''' which will do the following:
# Read a file from the directory. The files are read in the order they are copied into the directory, '''not alphabetical order'''!
# If the directories are the special links "." (current directory) or ".." (upper directory) it ignores them and goes to step 1 again.
# It prints out spaces to create a nicely formatted output. Each level of directory gets 2 spaces
# It prints out the name of the file in 8.3 format
# If it is a subdirectory, it makes a new object and opens up the subdirectory. Then it prints out all of the files in that new directory
# It continues to step 1 until there are no more files to be read
<nowiki>/*
* list recursively - possible stack overflow if subdirectories too nested
*/
void lsR(FatReader &d)
{
int8_t r; // indicates the level of recursion
while ((r = d.readDir(dirBuf)) > 0) { // read the next file in the directory
// skip subdirs . and ..
if (dirBuf.name[0] == '.')
continue;
for (uint8_t i = 0; i < dirLevel; i++)
Serial.print(' '); // this is for prettyprinting, put spaces in front
printName(dirBuf); // print the name of the file we just found
Serial.println(); // and a new line
if (DIR_IS_SUBDIR(dirBuf)) { // we will recurse on any direcory
FatReader s; // make a new directory object to hold information
dirLevel += 2; // indent 2 spaces for future prints
if (s.open(vol, dirBuf))
lsR(s); // list all the files in this directory now!
dirLevel -=2; // remove the extra indentation
}
}
sdErrorCheck(); // are we doign OK?
}
</nowiki>
There is also a helper called '''printName''' which prints out the file in a nice format. Files are named in '''8.3''' format, an older and simpler way of addressing files. Its a little less pretty than "Long Name Format" so watch out to see what your files are renamed as. For example "Bird song.wav" may be renamed to "BIRDSONG.WAV" or "BIRDSO~1.WAV" !
<nowiki>/*
* print dir_t name field. The output is 8.3 format, so like SOUND.WAV or FILENAME.DAT
*/
void printName(dir_t &dir)
{
for (uint8_t i = 0; i < 11; i++) { // 8.3 format has 8+3 = 11 letters in it
if (dir.name[i] == ' ')
continue; // dont print any spaces in the name
if (i == 8)
Serial.print('.'); // after the 8th letter, place a dot
Serial.print(dir.name[i]); // print the n'th digit
}
if (DIR_IS_SUBDIR(dir))
Serial.print('/'); // directories get a / at the end
}
</nowiki>
One thing that appears in '''loop()''' is '''dir.rewind()'''. The reason we rewind a directory is that our Arduino code is very simple. It can go through the files in a directory but only 'forward', not backward (FAT format is kinda like that). So if you skipped a file and want to go back, or you've gone through the directory, you will need to call '''rewind()''' to set it back to the beginning!
== Playing all the files ==
The digital audio player plays all files in the card. To do that it recursively looks in every directory, just like lsR() above so the code looks somewhat similar. The big difference is we call the play() routine to play a file!
To start, pass a directory object (like root) to '''lsR()''' which will do the following:
# Read a file from the directory. The files are read in the order they are copied into the directory, '''not alphabetical order'''!
# If the directories are the special links "." (current directory) or ".." (upper directory) it ignores them and goes to step 1 again.
# It prints out spaces to create a nicely formatted output. Each level of directory gets 2 spaces
# It prints out the name of the file in 8.3 format
# If it is a subdirectory, it makes a new object and opens up the subdirectory. Then it plays all of the wave files in that new directory
# If it isn't a subdirectory, it will try to play the file by opening it as a Wave object. That requires looking through the file and trying to find a Wave header, etc. If it doesnt succeed it will print out that its not valid and skip to the next file
# If the wave file is valid, it will finally start the file by calling '''play()''' on the Wave object
# While the wave sound file is playing, it prints out a dot every 100 ms or so.
# It continues to step 1 until there are no more files to be read
<nowiki>/*
* play recursively - possible stack overflow if subdirectories too nested
*/
void play(FatReader &dir)
{
FatReader file;
while (dir.readDir(dirBuf) > 0) { // Read every file in the directory one at a time
// skip . and .. directories
if (dirBuf.name[0] == '.')
continue;
Serial.println(); // clear out a new line
for (uint8_t i = 0; i < dirLevel; i++)
Serial.print(' '); // this is for prettyprinting, put spaces in front
if (!file.open(vol, dirBuf)) { // open the file in the directory
Serial.println("file.open failed"); // something went wrong :(
while(1); // halt
}
if (file.isDir()) { // check if we opened a new directory
putstring("Subdir: ");
printName(dirBuf);
dirLevel += 2; // add more spaces
// play files in subdirectory
play(file); // recursive!
dirLevel -= 2;
}
else {
// Aha! we found a file that isnt a directory
putstring("Playing "); printName(dirBuf); // print it out
if (!wave.create(file)) { // Figure out, is it a WAV proper?
putstring(" Not a valid WAV"); // ok skip it
} else {
Serial.println(); // Hooray it IS a WAV proper!
wave.play(); // make some noise!
while (wave.isplaying) { // playing occurs in interrupts, so we print dots in realtime
putstring(".");
delay(100);
}
sdErrorCheck(); // everything OK?
// if (wave.errors)Serial.println(wave.errors); // wave decoding errors
}
}
}
}
}
</nowiki>
</nowiki>