Allow to override mixer throttle by global function

docs/Global Functions.md

@@ -25,6 +25,7 @@ _Global Functions_ (abbr. GF) are a mechanism allowing to override certain fligh
 | 4             | INVERT_ROLL                   | Inverts ROLL axis input for PID/PIFF controller |
 | 5             | INVERT_PITCH                  | Inverts PITCH axis input for PID/PIFF controller  |
 | 6             | INVERT_YAW                    | Inverts YAW axis input for PID/PIFF controller |
+| 7             | OVERRIDE_THROTTLE             | Override throttle value that is fed to the motors by mixer. Operand is scaled in us. `1000` means throttle cut, `1500` means half throttle |
 
 ## Flags
 
@@ -53,4 +54,23 @@ gf 0 1 0 4 0 0 0
 gf 1 1 0 5 0 0 0
 ```
 
-Inverts ROLL and PITCH input when Logic Condition `0` evaluates as `true`. Moving Pitch stick up will cause pitch down (up for rear facing camera). Moving Roll stick right will cause roll left of a quad (right in rear facing camera)
+Inverts ROLL and PITCH input when Logic Condition `0` evaluates as `true`. Moving Pitch stick up will cause pitch down (up for rear facing camera). Moving Roll stick right will cause roll left of a quad (right in rear facing camera)
+
+### Cut motors but keep other throttle bindings active
+
+`gf 0 1 0 7 0 1000 0`
+
+Sets Thhrottle output to `0%` when Logic Condition `0` evaluates as `true`
+
+### Set throttle to 50% and keep other throttle bindings active
+
+`gf 0 1 0 7 0 1500 0`
+
+Sets Thhrottle output to about `50%` when Logic Condition `0` evaluates as `true`
+
+### Set throttle control to different RC channel
+
+`gf 0 1 0 7 1 7 0`
+
+If Logic Condition `0` evaluates as `true`, motor throttle control is bound to RC channel 7 instead of throttle channel
+

src/main/common/global_functions.c

@@ -113,6 +113,12 @@ void globalFunctionsProcess(int8_t functionId) {
                     GLOBAL_FUNCTION_FLAG_ENABLE(GLOBAL_FUNCTION_FLAG_OVERRIDE_INVERT_YAW);
                 }
                 break;
+            case GLOBAL_FUNCTION_ACTION_OVERRIDE_THROTTLE:
+                if (conditionValue) {
+                    globalFunctionValues[GLOBAL_FUNCTION_ACTION_OVERRIDE_THROTTLE] = globalFunctionsStates[functionId].value;
+                    GLOBAL_FUNCTION_FLAG_ENABLE(GLOBAL_FUNCTION_FLAG_OVERRIDE_THROTTLE);
+                }
+                break;
         }
     }
 }

src/main/common/global_functions.h

@@ -36,6 +36,7 @@ typedef enum {
     GLOBAL_FUNCTION_ACTION_INVERT_ROLL,
     GLOBAL_FUNCTION_ACTION_INVERT_PITCH,
     GLOBAL_FUNCTION_ACTION_INVERT_YAW,
+    GLOBAL_FUNCTION_ACTION_OVERRIDE_THROTTLE,
     GLOBAL_FUNCTION_ACTION_LAST
 } globalFunctionActions_e;
 
@@ -46,6 +47,7 @@ typedef enum {
     GLOBAL_FUNCTION_FLAG_OVERRIDE_INVERT_ROLL = (1 << 3),
     GLOBAL_FUNCTION_FLAG_OVERRIDE_INVERT_PITCH = (1 << 4),
     GLOBAL_FUNCTION_FLAG_OVERRIDE_INVERT_YAW = (1 << 5),
+    GLOBAL_FUNCTION_FLAG_OVERRIDE_THROTTLE = (1 << 6),
 } globalFunctionFlags_t;
 
 typedef struct globalFunction_s {
@@ -69,6 +71,7 @@ extern uint64_t globalFunctionsFlags;
 #define GLOBAL_FUNCTION_FLAG(mask) (globalFunctionsFlags & (mask))
 
 PG_DECLARE_ARRAY(globalFunction_t, MAX_GLOBAL_FUNCTIONS, globalFunctions);
+extern int globalFunctionValues[GLOBAL_FUNCTION_ACTION_LAST];
 
 void globalFunctionsUpdateTask(timeUs_t currentTimeUs);
 float getThrottleScale(float globalThrottleScale);

src/main/flight/mixer.c

@@ -320,6 +320,13 @@ void FAST_CODE NOINLINE mixTable(const float dT)
     static int16_t throttlePrevious = 0;   // Store the last throttle direction for deadband transitions
 
     // Find min and max throttle based on condition.
+#ifdef USE_GLOBAL_FUNCTIONS
+    if (GLOBAL_FUNCTION_FLAG(GLOBAL_FUNCTION_FLAG_OVERRIDE_THROTTLE)) {
+        throttleMin = motorConfig()->minthrottle;
+        throttleMax = motorConfig()->maxthrottle;
+        mixerThrottleCommand = constrain(globalFunctionValues[GLOBAL_FUNCTION_ACTION_OVERRIDE_THROTTLE], throttleMin, throttleMax); 
+    } else
+#endif
     if (feature(FEATURE_3D)) {
         if (!ARMING_FLAG(ARMED)) throttlePrevious = PWM_RANGE_MIDDLE; // When disarmed set to mid_rc. It always results in positive direction after arming.