PPS capture: Add a param to enable / disable PPS capture module. This is important, since it takes over an FMU pin which can no longer be used for actuator output.

ROMFS/px4fmu_common/init.d/rcS

@@ -478,7 +478,10 @@ else
 	fi
 
 	# PPS capture driver (before pwm_out)
+	if param greater -s PPS_CAP_ENABLE 0
+	then
 		pps_capture start
+	fi
 
 	# Camera capture driver (before pwm_out)
 	if param greater -s CAM_CAP_FBACK 0

src/drivers/pps_capture/pps_capture_params.c

@@ -0,0 +1,49 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2021 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file pps_capture_params.c
+ * PPS Capture params
+ */
+/**
+ * PPS Capture Enable
+ *
+ * Enables the PPS capture module.
+ * This switches mode of FMU channel 7 to be the
+ * PPS input channel.
+ *
+ * @boolean
+ * @group GPS
+ * @reboot_required true
+ */
+PARAM_DEFINE_INT32(PPS_CAP_ENABLE, 0);