Greetings,
I have managed to get my LPC11U24 to play midi files.
One of the big problems I had along the way was that reading the LocalFileSystem, where I have put some .MID files, was very slow using fread(). My player kept stalling as the files could not be read quickly enough.
I was pointed to an example of how to use the LocalFileHandle class to speed it up. What had seemed to be an impossible task became possible.
What I am trying to do is repeatedly play all .MID files that have been copied to the LocalFileSystem. The documentation for LocalFileHandle is a bit sparse, to say the least. There does not appear to be a way to find files in the directory using LocalFileHandle itself (or is there?), so I kept the LocalFileSystem declaration and readdir() that I had been using, and then used the LocalFileHandle once I have a file name.
This seems to work just fine, But, (there is always a but) I have a problem. I found that after processing the second file (or if there was only one .MID file in the directory, after processing that file for the second time), my program comes to a grinding halt. I found that the close() call was not returning to me. I noticed at the point that the close() was done a second time, the LocalFileSystem files appeared again on the USB-attached PC, after being inaccessible while my program was running up to that point.
In desperation mode I tried commenting out the close(), and I actually got a bit further. I could then process many more files before I eventually got an open failure. I am not 100% sure my way of testing that the open was successful is correct, but I think it is telling the truth, and that this failure may be due to running out of memory, but that is just a wild guess on my part.
Below is a very much cut down version of what I am doing but which behaves the same way. It gets the same problem if it selects other file types that are on the the LocalFileSystem such as .BIN.
Anybody got any ideas?
#include "mbed.h"
DigitalOut l1(LED1);
LocalFileSystem local("local"); // Create the local filesystem under the name "local"
int main()
{
uint8_t FileBuffer[64];
int filecount=0;
while ( 1 )
{
printf("Main loop. opening dirctory\r\n");
DIR *d = opendir("/local");
struct dirent *p;
while((p = readdir(d)) != NULL)
{
if ( strstr(p->d_name,".MID") )
{
printf("Opening %s\r\n",p->d_name);
FILEHANDLE fh = local_file_open(p->d_name, O_RDONLY);
LocalFileHandle lfh(fh);
if ( fh == NULL )
{
fprintf(stderr,"local_file_open failed\n");
exit(1);
}
printf("local file open - %d\r\n",++filecount);
lfh.read(FileBuffer,64);
printf("Closing LocalFileHandle\r\n");
l1=1;
lfh.close();
l1=0;
printf("Closed\r\n");
} // twas a .MID file
} // all in directory
printf("Closing directory\r\n");
closedir(d);
printf("Directory closed\r\n");
} // forever
} // main
Greetings,
I have managed to get my LPC11U24 to play midi files.
One of the big problems I had along the way was that reading the LocalFileSystem, where I have put some .MID files, was very slow using fread(). My player kept stalling as the files could not be read quickly enough.
I was pointed to an example of how to use the LocalFileHandle class to speed it up. What had seemed to be an impossible task became possible.
What I am trying to do is repeatedly play all .MID files that have been copied to the LocalFileSystem. The documentation for LocalFileHandle is a bit sparse, to say the least. There does not appear to be a way to find files in the directory using LocalFileHandle itself (or is there?), so I kept the LocalFileSystem declaration and readdir() that I had been using, and then used the LocalFileHandle once I have a file name.
This seems to work just fine, But, (there is always a but) I have a problem. I found that after processing the second file (or if there was only one .MID file in the directory, after processing that file for the second time), my program comes to a grinding halt. I found that the close() call was not returning to me. I noticed at the point that the close() was done a second time, the LocalFileSystem files appeared again on the USB-attached PC, after being inaccessible while my program was running up to that point.
In desperation mode I tried commenting out the close(), and I actually got a bit further. I could then process many more files before I eventually got an open failure. I am not 100% sure my way of testing that the open was successful is correct, but I think it is telling the truth, and that this failure may be due to running out of memory, but that is just a wild guess on my part.
Below is a very much cut down version of what I am doing but which behaves the same way. It gets the same problem if it selects other file types that are on the the LocalFileSystem such as .BIN.
Anybody got any ideas?
#include "mbed.h" DigitalOut l1(LED1); LocalFileSystem local("local"); // Create the local filesystem under the name "local" int main() { uint8_t FileBuffer[64]; int filecount=0; while ( 1 ) { printf("Main loop. opening dirctory\r\n"); DIR *d = opendir("/local"); struct dirent *p; while((p = readdir(d)) != NULL) { if ( strstr(p->d_name,".MID") ) { printf("Opening %s\r\n",p->d_name); FILEHANDLE fh = local_file_open(p->d_name, O_RDONLY); LocalFileHandle lfh(fh); if ( fh == NULL ) { fprintf(stderr,"local_file_open failed\n"); exit(1); } printf("local file open - %d\r\n",++filecount); lfh.read(FileBuffer,64); printf("Closing LocalFileHandle\r\n"); l1=1; lfh.close(); l1=0; printf("Closed\r\n"); } // twas a .MID file } // all in directory printf("Closing directory\r\n"); closedir(d); printf("Directory closed\r\n"); } // forever } // main