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:

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.

Diff: SWUpdate.cpp

Revision:
0:e221363f7942
Child:
1:208de08b1a19
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SWUpdate.cpp	Mon Apr 21 00:20:05 2014 +0000
@@ -0,0 +1,96 @@
+
+// Software Update via Ethernet from forum - 
+// http://mbed.org/forum/mbed/topic/1183/
+#include "mbed.h"
+#include "SWUpdate.h"
+#include "HTTPClient.h"
+#include "HTTPText.h"
+#include "HTTPFile.h"
+#include <stdio.h>
+
+extern "C" void mbed_reset();
+
+#define DEBUG "SWup"
+#include <cstdio>
+#if (defined(DEBUG) && !defined(TARGET_LPC11U24))
+#define DBG(x, ...)  std::printf("[DBG %s %3d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
+#define WARN(x, ...) std::printf("[WRN %s %3d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
+#define ERR(x, ...)  std::printf("[ERR %s %3d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
+#define INFO(x, ...) std::printf("[INF %s %3d] "x"\r\n", DEBUG, __LINE__, ##__VA_ARGS__);
+#else
+#define DBG(x, ...)
+#define WARN(x, ...)
+#define ERR(x, ...)
+#define INFO(x, ...)
+#endif
+
+bool SoftwareUpdate(const char *url, const char * name, Reboot_T reboot) {
+    HTTPClient http;
+    //http.setTimeout( 15000 ); 
+    char fqurl[150];    // fully qualified url
+    char verfn[32];     // local version file
+    char fwfn[32];
+    bool result = false;    // many things can go wrong, assume failure
+    //char *verfn = "/local/VERSION.TXT";
+    char buf[50];
+        
+    INFO("SoftwareUpdate(%s,%s)", url, name);
+    snprintf(verfn, 32, "/local/%s.ver", name);
+
+    /* Read installed version string */
+    int inst_ver = -1;
+    FILE *fv = fopen(verfn, "r");
+    if (fv) {
+        fscanf(fv, "%d", &inst_ver);
+        fclose(fv);
+    }
+    INFO("  Installed version: %d", inst_ver);
+    
+    /* Download latest version string */
+    HTTPText server_ver("test message");
+    snprintf(fqurl, 150, "%s/%s.txt", url, name);
+    HTTPResult r = http.get(fqurl, buf, sizeof(buf));
+    if (r == HTTP_OK) {
+        int latest_ver = -1;
+        INFO("  read {%s}", buf);
+        sscanf(buf, "%d", &latest_ver);
+        INFO("  web version: %d", latest_ver);
+        if (inst_ver != latest_ver) {
+            INFO("  Downloading new firmware...");
+            sprintf(fwfn, "/local/%s%d.BIN", name, latest_ver);
+            snprintf(fqurl, 150, "%s/%s.bin", url, name);
+    
+            HTTPFile latest(fwfn);
+            r = http.get(fqurl, &latest);
+            if (r == HTTP_OK) {
+                sprintf(fwfn, "/local/%s%d.BIN", name, inst_ver);
+                INFO("  Firmware downloaded, removing old version (%s).", fwfn);
+//                if (remove(fwfn)) {
+                    ERR("  *** Failed to remove old version. ***");
+//                }
+                INFO("Updating stored version number.");
+                fv = fopen(verfn, "w");
+                if (fv) {
+                    int fr = fputs(buf, fv);
+                    if (fr < 0) {
+                        ERR("Failed (%d) to update stored version number.", fr);
+                        fclose( fv );
+                    } else {
+                        fclose( fv );
+                        if (reboot == AUTO_REBOOT) {
+                            WARN("Resetting...\n");
+                            wait_ms(200);
+                            mbed_reset();
+                        }
+                        result = true;
+                    }
+                }
+            } else {
+                WARN("Couldn't download lastest firmware.\n");
+            }
+        }
+    } else {
+        WARN("Couldn't check latest firmware version.\n");
+    }
+    return result;
+}