serial1wire MSP and multi-esc configuration logic, compatible with BLHeliSuite 14.0.0.3.2 (beta)

mad props to @4712

docs/API/MSP_extensions.md

@@ -110,6 +110,19 @@ sending this message for all adjustment range slots.
 | adjustmentFunction | uint8 | See below |
 | auxSwitchChannelIndex | uint8 | The Aux channel number used to perform the function (indexed from 0) |
 
+### MSP\_SET\_1WIRE
+
+The MSP\_SET\_1WIRE is used to enable serial1wire passthrough
+note: it would be ideal to disable this when armed
+
+| Command | Msg Id | Direction |
+|---------|--------|-----------|
+| MSP\_SET\_1WIRE  | 243 | to FC |
+
+| Data | Type | Notes |
+|------|------|-------|
+| esc id | uint8 | A monotonically increasing ID, from 0 to the number of escs -1 |
+
 #### AdjustmentIndex
 
 The FC maintains internal state for each adjustmentStateIndex, currently 4 simultaneous adjustment states are maintained.  Multiple adjustment ranges

src/main/io/serial_1wire.c

@@ -238,4 +238,4 @@ void usb1WirePassthrough(int8_t escIndex)
   }
 }
 
-#endif
+#endif

src/main/io/serial_1wire.h

@@ -27,5 +27,6 @@ typedef struct {
   uint32_t pinpos;
 } escHardware_t;
 
+void usb1WireInitialize();
 void usb1WirePassthrough(int8_t escIndex);
 #endif

src/main/io/serial_msp.c

@@ -85,6 +85,9 @@
 
 #include "serial_msp.h"
 
+#ifdef USE_SERIAL_1WIRE
+#include "io/serial_1wire.h"
+#endif
 static serialPort_t *mspSerialPort;
 
 extern uint16_t cycleTime; // FIXME dependency on mw.c
@@ -310,6 +313,7 @@ static const char * const boardIdentifier = TARGET_BOARD_IDENTIFIER;
 #define MSP_GPSSVINFO            164    //out message         get Signal Strength (only U-Blox)
 #define MSP_SERVO_MIX_RULES      241    //out message         Returns servo mixer configuration
 #define MSP_SET_SERVO_MIX_RULE   242    //in message          Sets servo mixer configuration
+#define MSP_SET_1WIRE            243    //in message          Sets 1Wire paththrough 
 
 #define INBUF_SIZE 64
 
@@ -1762,6 +1766,47 @@ static bool processInCommand(void)
         isRebootScheduled = true;
         break;
 
+#ifdef USE_SERIAL_1WIRE
+    case MSP_SET_1WIRE:
+        // get channel number
+        i = read8();
+        // we do not give any data back, assume channel number is transmitted OK
+        if (i==0xFF) {
+            // 0xFF -> preinitialize the Passthrough
+            // switch all motor lines HI
+            usb1WireInitialize();
+            // and come back rigth afterwards
+            // rem: App: Wait at least appx. 500 ms for BLHeli to jump into bootloader mode before try to connect any ESC
+        }
+        else {
+            // Check for channel number 0..ESC_COUNT-1
+            if (i < ESC_COUNT) {
+                // because we do not come back after calling usb1WirePassthrough
+                // proceed a success reply first
+                headSerialReply(0);
+                tailSerialReply();
+                //wait for all data is send
+                while (!isSerialTransmitBufferEmpty(mspSerialPort)) {
+                    delay(50);
+                }
+                // Start to activate here
+                // motor 1 => index 0
+                usb1WirePassthrough(i);
+                // MPS uart is active again
+            } else {
+                // ESC channel higher than max. allowed
+                // rem: BLHelilSuite will not support more than 8
+                // Client should check active Motors before preinitialize the Passthrough
+                // with MSP_MOTOR and check each value >0 and later call only active channels
+                // rem: atm not allowed channel mapping other than 0..x ascending
+                headSerialError(0);
+            }
+            // proceed as usual with MSP commands
+            // and wait to switch to next channel
+            // rem: App needs to call MSP_BOOT to deinitialize Passthrough
+        }
+        break;
+#endif
     default:
         // we do not know how to handle the (valid) message, indicate error MSP $M!
         return false;