HAL_PX4: improved oneshot support

this now supports oneshot properly on both IO and FMU

libraries/AP_HAL_PX4/RCOutput.cpp

@@ -102,6 +102,14 @@ void PX4RCOutput::set_freq_fd(int fd, uint32_t chmask, uint16_t freq_hz)
     // we can't set this per channel
     if (freq_hz > 50) {
         // we're being asked to set the alt rate
+        if (_output_mode == MODE_PWM_ONESHOT) {
+            /*
+              set a 1Hz update for oneshot. This periodic output will
+              never actually trigger, instead we will directly trigger
+              the pulse after each push()
+             */
+            freq_hz = 1;
+        }
         if (ioctl(fd, PWM_SERVO_SET_UPDATE_RATE, (unsigned long)freq_hz) != 0) {
             hal.console->printf("RCOutput: Unable to set alt rate to %uHz\n", (unsigned)freq_hz);
             return;
@@ -160,10 +168,6 @@ void PX4RCOutput::set_freq(uint32_t chmask, uint16_t freq_hz)
     if (freq_hz > 400) {
         freq_hz = 400;
     }
-    if (freq_hz == 400) {
-        // remember mask for fast channels
-        _fast_channel_mask = chmask;
-    }
     uint32_t primary_mask = chmask & ((1UL<<_servo_count)-1);
     uint32_t alt_mask = chmask >> _servo_count;
     if (primary_mask && _pwm_fd != -1) {
@@ -267,6 +271,11 @@ void PX4RCOutput::write(uint8_t ch, uint16_t period_us)
     if (ch >= _max_channel) {
         _max_channel = ch + 1;
     }
+    /*
+      only mark an update is needed if there has been a change, or we
+      are in oneshot mode. In oneshot mode we always need to send the
+      output
+     */
     if (period_us != _period[ch] ||
         _output_mode == MODE_PWM_ONESHOT) {
         _period[ch] = period_us;
@@ -478,44 +487,18 @@ void PX4RCOutput::push()
     if (_output_mode == MODE_PWM_ONESHOT) {
         // run timer immediately in oneshot mode
         _send_outputs();
-        if (_fast_channel_mask != 0) {
-            // this is a crude way of triggering immediate output
-            _trigger_fast_output();
-        }
     }
 }
 
 void PX4RCOutput::_timer_tick(void)
 {
     if (_output_mode != MODE_PWM_ONESHOT) {
+        /* in oneshot mode the timer does nothing as the outputs are
+         * sent from push() */
         _send_outputs();
     }
 }
 
-/*
-  trigger immediate output on fast channels. This only works on FMU,
-  not IO. It takes advantage of the way the rate update works on FMU
-  to trigger a oneshot output
- */
-void PX4RCOutput::_trigger_fast_output(void)
-{
-    uint32_t primary_mask = _fast_channel_mask & ((1UL<<_servo_count)-1);
-    uint32_t alt_mask = _fast_channel_mask >> _servo_count;    
-    if (_alt_fd == -1) {
-        // we're on a FMU only board
-        if (primary_mask) {
-            set_freq_fd(_pwm_fd, primary_mask, 400);
-            set_freq_fd(_pwm_fd, primary_mask, 51);
-        }
-    } else {
-        // we're on a board with px4io
-        if (alt_mask) {
-            set_freq_fd(_alt_fd, alt_mask, 400);
-            set_freq_fd(_alt_fd, alt_mask, 51);
-        }
-    }
-}
-
 /*
   enable sbus output
  */
@@ -548,8 +531,15 @@ void PX4RCOutput::set_output_mode(enum output_mode mode)
     _output_mode = mode;
     if (_output_mode == MODE_PWM_ONESHOT) {
         ioctl(_pwm_fd, PWM_SERVO_SET_ONESHOT, 1);
+        if (_alt_fd != -1) {
+            ioctl(_alt_fd, PWM_SERVO_SET_ONESHOT, 1);
+        }
+        set_freq(0xFFFF, 51);
     } else {
         ioctl(_pwm_fd, PWM_SERVO_SET_ONESHOT, 0);
+        if (_alt_fd != -1) {
+            ioctl(_alt_fd, PWM_SERVO_SET_ONESHOT, 0);
+        }
     }
 }
 

libraries/AP_HAL_PX4/RCOutput.h

@@ -61,7 +61,6 @@ private:
     orb_advert_t _actuator_armed_pub = NULL;
     uint16_t _esc_pwm_min = 0;
     uint16_t _esc_pwm_max = 0;
-    uint16_t _fast_channel_mask;
 
     void _init_alt_channels(void);
     void _publish_actuators(void);
@@ -70,6 +69,4 @@ private:
     bool _corking;
     enum output_mode _output_mode = MODE_PWM_NORMAL;
     void _send_outputs(void);
-
-    void _trigger_fast_output();
 };