Revise handling of msp CRC errors to prevent referencing undefined objects and allow blackbox packets to retry

js/msp.js

@@ -11,6 +11,7 @@ var MSP = {
     message_buffer_uint8_view:  null,
     message_checksum:           0,
     messageIsJumboFrame:        false,
+    crcError:                   false,
 
     callbacks:                  [],
     packet_error:               0,
@@ -114,14 +115,16 @@ var MSP = {
                         this.dataView = new DataView(this.message_buffer, 0, this.message_length_expected);
                     } else {
                         console.log('code: ' + this.code + ' - crc failed');
-                        this.dataView = null;
                         this.packet_error++;
+                        this.crcError = true;
+                        this.dataView = new DataView(new ArrayBuffer(0));
                     }
                     // Reset variables
                     this.message_length_received = 0;
                     this.state = 0;
                     this.messageIsJumboFrame = false;
                     this.notify();
+                    this.crcError = false;
                     break;
 
                 default:
@@ -144,10 +147,15 @@ var MSP = {
     clearListeners: function() {
         this.listeners = [];  
     },
-    send_message: function (code, data, callback_sent, callback_msp) {
+    send_message: function (code, data, callback_sent, callback_msp, callback_onerror) {
         var bufferOut,
             bufView;
 
+         if (callback_onerror === undefined) {
+             var callbackOnError = false;
+         } else {
+             var callbackOnError = true;
+         }
         // always reserve 6 bytes for protocol overhead !
         if (data) {
             var size = data.length + 6,
@@ -183,7 +191,7 @@ var MSP = {
             bufView[5] = bufView[3] ^ bufView[4]; // checksum
         }
 
-        var obj = {'code': code, 'requestBuffer': bufferOut, 'callback': (callback_msp) ? callback_msp : false, 'timer': false};
+        var obj = {'code': code, 'requestBuffer': bufferOut, 'callback': (callback_msp) ? callback_msp : false, 'timer': false, 'callbackOnError': callbackOnError};
 
         var requestExists = false;
         for (var i = 0; i < MSP.callbacks.length; i++) {

js/msp/MSPHelper.js

@@ -52,6 +52,8 @@ MspHelper.prototype.process_data = function(dataHandler) {
 
     var data = dataHandler.dataView; // DataView (allowing us to view arrayBuffer as struct/union)
     var code = dataHandler.code;
+    var crcError = dataHandler.crcError;
+    if (!crcError) {
         if (!dataHandler.unsupported) switch (code) {
             case MSPCodes.MSP_STATUS:
                 CONFIG.cycleTime = data.readU16();
@@ -943,21 +945,23 @@ MspHelper.prototype.process_data = function(dataHandler) {
         } else {
             console.log('FC reports unsupported message error: ' + code);
         }
-
+    }
     // trigger callbacks, cleanup/remove callback after trigger
     for (var i = dataHandler.callbacks.length - 1; i >= 0; i--) { // itterating in reverse because we use .splice which modifies array length
         if (dataHandler.callbacks[i].code == code) {
             // save callback reference
             var callback = dataHandler.callbacks[i].callback;
+            var callbackOnError = dataHandler.callbacks[i].callbackOnError;
 
             // remove timeout
             clearInterval(dataHandler.callbacks[i].timer);
 
             // remove object from array
             dataHandler.callbacks.splice(i, 1);
-
+            if (!crcError || callbackOnError) {
                 // fire callback
-            if (callback) callback({'command': code, 'data': data, 'length': data.byteLength});
+                if (callback) callback({'command': code, 'data': data, 'length': data.byteLength, 'crcError': crcError});
+            }
         }
     }
 }
@@ -1268,6 +1272,7 @@ MspHelper.prototype.dataflashRead = function(address, blockSize, onDataCallback)
     }
 
     MSP.send_message(MSPCodes.MSP_DATAFLASH_READ, outData, false, function(response) {
+        if (!response.crcError) {
             var chunkAddress = response.data.readU32();
 
             var headerSize = 4;
@@ -1279,17 +1284,23 @@ MspHelper.prototype.dataflashRead = function(address, blockSize, onDataCallback)
                 dataCompressionType = response.data.readU8();
             }
 
-        // Verify that the address of the memory returned matches what the caller asked for
+            // Verify that the address of the memory returned matches what the caller asked for and there was not a CRC error
             if (chunkAddress == address) {
                 /* Strip that address off the front of the reply and deliver it separately so the caller doesn't have to
                  * figure out the reply format:
                  */
                 onDataCallback(address, new DataView(response.data.buffer, response.data.byteOffset + headerSize, dataSize));
             } else {
-            // Report error
+                // Report address error
-            onDataCallback(address, null);
+                console.log('Expected address ' + address + ' but received ' + chunkAddress + ' - retrying');
+                onDataCallback(address, null);  // returning null to the callback forces a retry
             }
-    });
+        } else {
+            // Report crc error
+            console.log('CRC error for address ' + address + ' - retrying');
+            onDataCallback(address, null);  // returning null to the callback forces a retry
+        }
+    },true);
 };
 
 MspHelper.prototype.sendServoConfigurations = function(onCompleteCallback) {