Enumerating as a serial device and a USB disk

Forum 2005-2010 (read only) Hardware Development
1

Has anyone ever tried to have the Arduino enumerate (from the PC) as both a serial device and a USB flash device?

It would be nice to drag and drop files to some NAND chip (on the Arduino PCB) that both my PC and the Arduino can see.

Specifically, I'm trying to create a PC watchdog recovery system where my pc computer would boot into recovery mode if either the PC hard disk failed, crash, hung, etc, or if the PC needed to be re-imaged.

For example:

  1. PC boots
  2. BIOS sees USB-HDD Arduino device and boots this over the hard disk
  3. USB-HDD Arduino device runs code to see whether it needs to boot or whether it should chainload the boot to the next device (the hard drive). If it determined that there was x unsuccessful boot attempts, the USB-HDD boots itself and recovery software is loaded. The PC is now in recovery mode.
  4. Whether the PC hard drive boots or whether the USB-HDD Arduino boots, a watchdog timer is started on the Arduino and you would use the serial interface to reset the watchdog timer.

Note: You can also use the DIO ports for Arduino to show LED status, ring a buzzer for an expired watchdog, or even reset the PC computer if a driver crashed or the OS is unresponsive.

Any ideas on how to do this, or perhaps point me into the right direction? Thanks in advance!

2

Short answer is that the Arduino boards use a dedicated serial-to-usb converter chip and can't appear as any other sort of USB device.

With an expansion shield and code integrating Arduino and AVRUSB it is possible for the Arduino to act (somewhat) as a low-speed USB device but you wouldn't be operating within the USB spec.

Atmel do sell "proper" USB-capable devices but I don't think the Arduino environment has been ported to them.

--Phil.