Hi,

I haven't tried this yet so I may be off but as far as I understood it, the MBED mass storage (2Mb) is shared between MBED applications and the MBED control chip.  Since this arrangement requires that only one "master" is active in a given moment, this ought to lead to fairly erratic operation if connected to a PC (the OS will connnect and disconnect all the time).

Having a call that disables the MBED control chip would kill reflashing so that's not an option either.

Would it be possible to add a call where you requested exclusivity but had an "unlock" connected to a device I/O pin?

Anders

Hi Anders,

The logic of the interface is that the USB drive is "removed" from the host when the mbed requests to open any files, and restored to the host when mbed has closed all files. So, for example, if you open a file and just keep appending to it, mbed holds on to it until you finally close it.

If you want to keep opening and closing all files yet stop it giving back to the host, you could possibly open a dummy file, and close it when you wanted to release it back to the host?

Hope that helps,

Simon

Thanx Simon,

I think I had gotten it wrong because I did not realize that holding down the reset button does not stop the MBED interface chip, only the MCU, so that there is no risk of locking up MBED like when you take exclusive oweneship over mass storage.  This's is of course a very smart thing :-)

Your suggestion should (if my assumption above is correct) be a perfect solution to what I wanted to do.

Thanxs again, I really appreciate the quick response.

Anders