David Smart / SWUpdate Featured

Software Update via Ethernet - the mbed application can pull down an updated application binary from a web server and activate that binary. This library works only with the LPC1768, as it relies on the magic-chip boot-loader mechanism.

Dependents:   WattEye X10Svr PUB_SWUpdate

Success!! With this library, a network connection, and a web server hosting a new binary image, you can update the mbed firmware over the air (FOTA) - well, at least via Ethernet so far.

As of March 2015, it has been tested with the following mbed official libraries:

• mbed v95, v85 thru v89
• mbed-rtos v64, v32 thru v44
• EthernetInterface v47, v41 thru v43

And a custom derivation:

• HTTPClient v33, v32, which includes a custom HTTPFile.

Part of the update process involves checking the integrity of the downloaded binary file, for both a checksum and the program (file) size. To create this additional information, a small perl script is used (the important part is only 20 lines of code). See the documentation in the header file.

After the new binary is successfully downloaded, the checksum and the size are evaluated and if correct, then the old binary file is removed (this is the only way to cause the new binary to activate).

The mbed can then be automatically reset to activate the new image, or this may be deferred in case there is some other process necessary for an orderly restart.

Details are in the SWUpdate header file, and PUB_SWUpdate is a publicly accessible demonstration program for this library.

#include "mbed.h"

#ifndef SWUPDATE_H
#define SWUPDATE_H

/// After downloading, the user can choose what happens next.
typedef enum {
    DEFER_REBOOT,
    AUTO_REBOOT
} Reboot_T;

/// This API performs some processing to see if a web server
/// has an updated version of software. If it does, then it
/// will try to download it. If that succeeds, then it can
/// optionally reboot to activate the new software.
///
/// @todo check the freshly downloaded sw integrity. Since we have
///     to remove the old .bin file before the new one will execute,
///     it is in the device' best interest to ensure that new one
///     is a good one.
///
/// @param url is a pointer to a text string of the url from which to download.
/// @param name is the base filename of the binary file.
/// @param reboot determines whether to automatically reboot to activate the new bin.
/// @return true if the update succeeded (and the reboot was set to DEFER_REBOOT).
///
bool SoftwareUpdate(const char *url, const char * name, Reboot_T reboot = DEFER_REBOOT);

#endif // SWUPDATE_H