AP_Motors: added oneshot support via MOT_PWM_MODE

MOT_PWM_MODE=0 is normal
MOT_PWM_MODE=1 is oneshot
MOT_PWM_MODE=2 is oneshot125

libraries/AP_Motors/AP_MotorsMulticopter.cpp

@@ -98,6 +98,13 @@ const AP_Param::GroupInfo AP_MotorsMulticopter::var_info[] = {
     // @User: Advanced
     AP_GROUPINFO("THR_MIX_MAX", 14, AP_MotorsMulticopter, _thr_mix_max, AP_MOTORS_THR_MIX_MAX_DEFAULT),
 
+    // @Param: PWM_MODE
+    // @DisplayName: Output PWM mode
+    // @Description: This selects the output PWM mode, allowing for normal PWM continuous output or OneShot125
+    // @Values: 0:Normal,1:OneShot,2:OneShot125
+    // @User: Advanced
+    AP_GROUPINFO("PWM_MODE", 15, AP_MotorsMulticopter, _pwm_mode, PWM_MODE_NORMAL),
+    
     AP_GROUPEND
 };
 

libraries/AP_Motors/AP_Motors_Class.cpp

@@ -79,6 +79,10 @@ void AP_Motors::rc_write(uint8_t chan, uint16_t pwm)
         // we have a mapped motor number for this channel
         chan = _motor_map[chan];
     }
+    if (_pwm_mode == PWM_MODE_ONESHOT125) {
+        // OneShot125 uses a PWM range from 125 to 250 usec
+        pwm /= 8;
+    }
     hal.rcout->write(chan, pwm);
 }
 
@@ -88,6 +92,11 @@ void AP_Motors::rc_write(uint8_t chan, uint16_t pwm)
 void AP_Motors::rc_set_freq(uint32_t mask, uint16_t freq_hz)
 {
     hal.rcout->set_freq(rc_map_mask(mask), freq_hz);
+    if (_pwm_mode == PWM_MODE_ONESHOT ||
+        _pwm_mode == PWM_MODE_ONESHOT125) {
+        // tell HAL to do immediate output
+        hal.rcout->set_output_mode(AP_HAL::RCOutput::MODE_PWM_ONESHOT);
+    }
 }
 
 void AP_Motors::rc_enable_ch(uint8_t chan)

libraries/AP_Motors/AP_Motors_Class.h

@@ -179,4 +179,7 @@ protected:
     float _pitch_radio_passthrough = 0.0f;    // pitch input from pilot in -1 ~ +1 range.  used for setup and providing servo feedback while landed
     float _throttle_radio_passthrough = 0.0f; // throttle/collective input from pilot in 0 ~ 1 range.  used for setup and providing servo feedback while landed
     float _yaw_radio_passthrough = 0.0f;      // yaw input from pilot in -1 ~ +1 range.  used for setup and providing servo feedback while landed
+
+    enum pwm_mode { PWM_MODE_NORMAL=0, PWM_MODE_ONESHOT=1, PWM_MODE_ONESHOT125=2 };
+    AP_Int8             _pwm_mode;            // PWM output mode
 };