In the previous two mails [1, 2], I described how to load the firmware (boot loader and application) into an atusb for the first time. This is usually done when the device is manufactured or by a developer who wishes to modify the boot loader.
All other users (end users, but also developers modifying the atusb application) should never need to replace the boot loader. Yet, they may want to update the application. For this, the process outlined in this mail should be used. Background: the atusb firmware consists of a DFU-capable boot loader and the actual application. It is the application that moves data between USB and the RF chip. When atusb is powered up, it first runs the boot loader. The boot loader has its own USB stack and enumerates as a device supporting the USB Device Firmware Upgrade (DFU) protocol. [3] Then the boot loader accepts DFU commands for 2 seconds. If no DFU commands are sent in this period, the boot loader resets the USB bus and starts the application. While waiting, the boot loader lights the LED of the atusb board. To update the application, you need: - Hardware - a atusb board (with boot loader) - a PC running Linux with an available USB port - Software - dfu-util, running on the PC - the atusb application (firmware) binary Instructions for obtaining dfu-util and the atusb application can be found in [2]. To update the application, perform these steps: - remove atusb from the Linux PC - prepare to run the following command: dfu-util -d 20b7:1540 -D atusb.bin - plug atusb into the PC - wait about one second to give the PC's USB stack time to enumerate the new device - run the dfu-util command above dfu-util should run for about 1-2 seconds, showing a progress bar, and then report success. The LED stays lit while dfu-util runs. Once dfu-util finishes, the boot loader waits two more seconds, then turns off the LED and starts the application. If dfu-util reports an error, you may have missed the right moment to start dfu-util. Unplug atusb and try again. Note that this process works always, no matter in which condition the application is. E.g., if you've loaded a defective application that "bricks" the atusb, you can still replace it following this procedure. In the next mail, I'll describe a more sophisticated process for updating the atusb application. [1] http://lists.en.qi-hardware.com/pipermail/discussion/2011-May/008004.html [2] http://lists.en.qi-hardware.com/pipermail/discussion/2011-May/008005.html [3] http://www.usb.org/developers/devclass_docs/DFU_1.1.pdf - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
