First cut of allowing a 3POS switch on AUX3 to change rc rate.

rcRate is decreased when low, increased when HIGH and no change when the
switch is in the middle.

The rcRate ticks up/down at 0.01 every 500ms if the switch is left on.

If using a momentary switch and if you can toggle the switch between
middle and low or middle and high more frequently than 500ms then the
rate will be increased accordingly.  Similar to how a keyboard repeat
behaves.

src/test/unit/rc_controls_unittest.cc

@@ -157,6 +157,221 @@ TEST(RcControlsTest, updateActivatedModesUsingValidAuxConfigurationAndRXValues)
     }
 }
 
+enum {
+    COUNTER_GENERATE_PITCH_ROLL_CURVE = 0
+};
+#define CALL_COUNT_ITEM_COUNT 1
+
+static int callCounts[CALL_COUNT_ITEM_COUNT];
+
+#define CALL_COUNTER(item) (callCounts[item])
+
+void generatePitchRollCurve(controlRateConfig_t *) {
+    callCounts[COUNTER_GENERATE_PITCH_ROLL_CURVE]++;
+}
+
+void resetCallCounters(void) {
+    memset(&callCounts, 0, sizeof(callCounts));
+}
+
+uint32_t fixedMillis = 0;
+
+uint32_t millis(void) {
+    return fixedMillis;
+}
+
+#define DEFAULT_MIN_CHECK 1100
+#define DEFAULT_MAX_CHECK 1900
+
+rxConfig_t rxConfig;
+
+extern uint32_t adjustmentFunctionStateMask;
+
+TEST(RcControlsTest, processRcAdjustmentsSticksInMiddle)
+{
+    // given
+    controlRateConfig_t controlRateConfig = {
+            .rcRate8 = 90,
+            .rcExpo8 = 0,
+            .thrMid8 = 0,
+            .thrExpo8 = 0,
+            .rollPitchRate = 0,
+            .yawRate = 0,
+    };
+
+    // and
+    memset(&rxConfig, 0, sizeof (rxConfig));
+    rxConfig.mincheck = DEFAULT_MIN_CHECK;
+    rxConfig.maxcheck = DEFAULT_MAX_CHECK;
+
+    // and
+    uint8_t index;
+    for (index = AUX1; index < MAX_SUPPORTED_RC_CHANNEL_COUNT; index++) {
+        rcData[index] = PWM_RANGE_MIDDLE;
+    }
+
+    // and
+    resetCallCounters();
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 90);
+    EXPECT_EQ(CALL_COUNTER(COUNTER_GENERATE_PITCH_ROLL_CURVE), 0);
+    EXPECT_EQ(adjustmentFunctionStateMask, 0);
+}
+
+TEST(RcControlsTest, processRcAdjustmentsWithRcRateFunctionSwitchUp)
+{
+    // given
+    controlRateConfig_t controlRateConfig = {
+            .rcRate8 = 90,
+            .rcExpo8 = 0,
+            .thrMid8 = 0,
+            .thrExpo8 = 0,
+            .rollPitchRate = 0,
+            .yawRate = 0,
+    };
+
+    // and
+    memset(&rxConfig, 0, sizeof (rxConfig));
+    rxConfig.mincheck = DEFAULT_MIN_CHECK;
+    rxConfig.maxcheck = DEFAULT_MAX_CHECK;
+
+    // and
+    uint8_t index;
+    for (index = AUX1; index < MAX_SUPPORTED_RC_CHANNEL_COUNT; index++) {
+        rcData[index] = PWM_RANGE_MIDDLE;
+    }
+
+    // and
+    resetCallCounters();
+
+    // and
+    rcData[AUX3] = PWM_RANGE_MAX;
+
+    // and
+    uint32_t expectedAdjustmentFunctionStateMask =
+            (1 << (ADJUSTMENT_RC_RATE - ADJUSTMENT_INDEX_OFFSET));
+
+    // and
+    fixedMillis = 496;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 91);
+    EXPECT_EQ(CALL_COUNTER(COUNTER_GENERATE_PITCH_ROLL_CURVE), 1);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+
+    //
+    // now pretend a short amount of time has passed, but not enough time to allow the value to have been increased
+    //
+
+    // given
+    fixedMillis = 497;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    EXPECT_EQ(controlRateConfig.rcRate8, 91);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+
+    //
+    // moving the switch back to the middle should immediately reset the state flag without increasing the value
+    //
+
+
+    // given
+    rcData[AUX3] = PWM_RANGE_MIDDLE;
+
+    // and
+    fixedMillis = 498;
+
+    // and
+    expectedAdjustmentFunctionStateMask = adjustmentFunctionStateMask &
+            ~(1 << (ADJUSTMENT_RC_RATE - ADJUSTMENT_INDEX_OFFSET));
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    EXPECT_EQ(controlRateConfig.rcRate8, 91);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+
+    //
+    // flipping the switch again, before the state reset would have occurred, allows the value to be increased again
+
+    // given
+    rcData[AUX3] = PWM_RANGE_MAX;
+
+    // and
+    expectedAdjustmentFunctionStateMask =
+            (1 << (ADJUSTMENT_RC_RATE - ADJUSTMENT_INDEX_OFFSET));
+
+    // and
+    fixedMillis = 499;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 92);
+    EXPECT_EQ(CALL_COUNTER(COUNTER_GENERATE_PITCH_ROLL_CURVE), 2);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+    //
+    // leaving the switch up, after the original timer would have reset the state should now NOT cause
+    // the rate to increase, it should only increase after another 500ms from when the state was reset.
+    //
+
+    // given
+    fixedMillis = 500;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 92);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+    //
+    // should still not be able to be increased
+    //
+
+    // given
+    fixedMillis = 997;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 92);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+    //
+    // 500ms has now passed since the switch was returned to the middle, now that
+    // switch is still in the UP position after the timer has elapses it should
+    // be increased again.
+    //
+
+    // given
+    fixedMillis = 998;
+
+    // when
+    processRcAdjustments(&controlRateConfig, &rxConfig);
+
+    // then
+    EXPECT_EQ(controlRateConfig.rcRate8, 93);
+    EXPECT_EQ(CALL_COUNTER(COUNTER_GENERATE_PITCH_ROLL_CURVE), 3);
+    EXPECT_EQ(adjustmentFunctionStateMask, expectedAdjustmentFunctionStateMask);
+
+}
+
 void changeProfile(uint8_t) {}
 void accSetCalibrationCycles(uint16_t) {}
 void gyroSetCalibrationCycles(uint16_t) {}