creating and writing files to flash / MES | Telit Cinterion IoT Developer Community
June 12, 2014 - 3:55pm, 7773 views
Hi again and thanks for your last helpful answer, Jedrzej,
I now have some questions about writing data to files on the flash system.
1. Is there a way to directly write to flash using the java api or can this only be accomplished using AT^SFSA commands?
2. I have successfully created and opened a new file using this:
response = m_Cmd.send("AT^SFSA=\"open\"," + filename + ",8\r");
System.out.println(response);
But how do I go about writing data to the file, any examples?
I'd like to then upload the file via ftp to a remote server.
3. I have noticed that sometimes I can't access the flash using Windows Explorer i.e. Module a:/
This definitively appears to happen when Netbeans is running and probably taking over the Comport. It is a bit of a nuisance to keep closing and opening the IDE and restarting the cinterion board just to have access to the flash. Using the MES with e.g. MESDir mod:a:/ also doesn't work unless I have done a PC and cinterion board reboot and NOT run netbeans yet.
Any idea or alternatives about this can be improved?
Jun 12 2014 - 5:43pm
Hello!
You're welcome.
Ad.1. You can use FileConnection Interface described in JSR75 lib reference. You can access a file on drive A: using following code:
FileConnection fconn = (FileConnection)Connector.open("file:///a:/testFile.txt");
Check the docu for details.
Ad.2. It seems that in your case using FileConnection is better solution as you're using Java. However, here you've got AT log example of AT^SFSA usage :
at^sfsa="open","a:/testfile.txt",8 <-- create file
^SFSA: 0,0 <-- opened, file handle is 0
OK
at^sfsa="write",0,10 <-- write 10 bytes to file 0
CONNECT
<-- here I wrote 10 bytes: abcde12345
^SFSA: 0
OK
at^sfsa="close",0 <-- closing file 0
^SFSA: 0
OK
at^sfsa="open","a:/testfile.txt",0 <-- open existing file
^SFSA: 0,0 <-- file handle is 0
OK
at^sfsa="read",0,100 <-- request max 100 bytes
^SFSA: 10,0 <-- 10 bytes returned
abcde12345 <-- here it is!
OK
Ad.3. I assume you're using Concept Board. If you're restarting the board while some of usb com ports are still open, they enumerate after reboot, but are not usable. Always release com ports before reboot. It may be that netbeans is holding some of com ports.
Onboard ASC0 connector is invulnerable to resetting the board. Switch MES to use this one.
Best regards
Jedrzej
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Jun 12 2014 - 6:38pm
Hi Jedrzej,
Many thanks for your quick reply. I'll have a look at JSR75. In the meantime I'll just go with AT^SFSA...
As I'm new to Java, what's the actual write command to send characters or a string to the file after issuing for example:
response = m_Cmd.send("AT^SFSA=\"write\",0,10\r");
Also, what is the corresponding read command?
concerning Ad.3:
Yes, I'm using the concept board. I generally restart the board by unplugging USB connection from the board which should release it, then plugging it back in and finally restart it by pressing the START button. I have checked often in Device Manager and it does not change as I use the same physical ports. It appears that netbeans hogs the port even after a close and restart of the IDE. Have you encountered this?
Thanks again,
Micha
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Jun 13 2014 - 6:54pm
Hello,
I would recommend using FileConnection due to performance and convenience of usage. If using AT^SFSA from Java you'd have to implement SFSA parsing and handling which is not needed when using FileConnection API.
To effectively write you need to open output stream:
OutputStream os = m_Cmd.getDataOutputStream();
and write to it:
os.write("some data".getBytes());
also flushing the buffer may be necessary:
os.flush();
Yes, it doesn't change port numbers, but they will not be usable if rebooting was performed when at least one virtual com port was open at the time of reboot. Avoid unplugging the usb. Try to restart the board with AT+CFUN=1,1 or AT^SMSO via ASC0.
Regards
Jedrzej
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Jun 16 2014 - 7:50pm
Hi Jedrzej,
Thanks for that, I am now using the recommended FileConnection method and my midlet is able to create files. Unfortunately I have a small but annoying bug that results in the fixed filenames working but constructed ( using + substring() ) not working. I have read up about how Java strings are constructed but have not understood how this would apply in this case. Any idea? :-)
Many thanks,
Micha
Code:
filename_new = "file:///a:/" + filename.substring(32,34)" + ".txt"; // this does not work
// filename_new = "file:///a:/zzz.dat"; // this declared string constant works
try
{
System.out.println("opening FileConnection...");
fc = (FileConnection) Connector.open(filename_new, Connector.READ_WRITE);
if (!fc.exists())
{
System.out.println("creating file... ");
fc.create(); // create the file if it doesn't exist
}
System.out.println("opening stream... ");
DataOutputStream dos = fc.openDataOutputStream();
System.out.println("writing data... ");
dos.writeUTF("DateTimeStamp: " + filename_new);
System.out.println("flushing stream buffer... ");
dos.flush();
}
catch (Exception e) {System.out.println(e);}
finally
{
try
{
System.out.println("closing fc... ");
fc.close();
}
catch (IOException e) {}
}
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Jun 17 2014 - 11:11am
Hello,
What are the values of filename and filename_new variables? Sysout it to check what argument is passed to Connector.open method.
Regards
Jedrzej
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Jun 17 2014 - 3:15pm
Thanks for your reply, Jedrzej, got it working... :-)
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