From e22c8b27a9ee46f5312a51e77040f8e14a86e456 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Thu, 6 Nov 2014 17:29:14 +1100
Subject: [PATCH] HAL_PX4: if there are no enabled channels don't send to PX4IO

this makes it possible to disable PWM output to IO to test override
---
 libraries/AP_HAL_PX4/RCOutput.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libraries/AP_HAL_PX4/RCOutput.cpp b/libraries/AP_HAL_PX4/RCOutput.cpp
index d8a4fecb2b..b17a21e62f 100644
--- a/libraries/AP_HAL_PX4/RCOutput.cpp
+++ b/libraries/AP_HAL_PX4/RCOutput.cpp
@@ -243,6 +243,11 @@ void PX4RCOutput::_timer_tick(void)
 {
     uint32_t now = hal.scheduler->micros();
 
+    if ((_enabled_channels & ((1U<<_servo_count)-1)) == 0) {
+        // no channels enabled
+        goto update_pwm;
+    }
+
     // always send at least at 20Hz, otherwise the IO board may think
     // we are dead
     if (now - _last_output > 50000) {