Adressed performance concern and fixed a copy paste bug

src/drivers/px4io/px4io.cpp

@@ -1851,7 +1851,7 @@ px4io_main(int argc, char *argv[])
 					}
 				} else {
 					/* a zero value will the default */
-					min[i] = 900;
+					min[i] = 0;
 				}
 			}
 
@@ -1886,7 +1886,7 @@ px4io_main(int argc, char *argv[])
 					}
 				} else {
 					/* a zero value will the default */
-					max[i] = 2100;
+					max[i] = 0;
 				}
 			}
 

src/modules/px4iofirmware/mixer.cpp

@@ -62,7 +62,7 @@ extern "C" {
 /*
  * Time that the ESCs need to initialize
  */
- #define ESC_INIT_TIME_US		500000
+ #define ESC_INIT_TIME_US		2000000
 
 /* XXX need to move the RC_CHANNEL_FUNCTION out of rc_channels.h and into systemlib */
 #define ROLL     0
@@ -75,6 +75,7 @@ extern "C" {
 static bool mixer_servos_armed = false;
 
 static uint64_t time_armed;
+static bool init_complete = false;
 
 /* selected control values and count for mixing */
 enum mixer_source {
@@ -177,6 +178,10 @@ mixer_tick(void)
 		/* mix */
 		mixed = mixer_group.mix(&outputs[0], IO_SERVO_COUNT);
 
+		if (!init_complete && mixer_servos_armed && (hrt_elapsed_time(&time_armed) > ESC_INIT_TIME_US)) {
+			init_complete = true;
+		}
+
 		/* scale to PWM and update the servo outputs as required */
 		for (unsigned i = 0; i < mixed; i++) {
 
@@ -184,7 +189,7 @@ mixer_tick(void)
 			r_page_actuators[i] = FLOAT_TO_REG(outputs[i]);
 
 			/* scale to control range after init time */
-			if (mixer_servos_armed && (hrt_elapsed_time(&time_armed) > ESC_INIT_TIME_US)) {
+			if (init_complete) {
 				r_page_servos[i] = (outputs[i]
 					* (r_page_servo_control_max[i] - r_page_servo_control_min[i])/2
 					+ (r_page_servo_control_max[i] + r_page_servo_control_min[i])/2);
@@ -222,11 +227,13 @@ mixer_tick(void)
 		up_pwm_servo_arm(true);
 		mixer_servos_armed = true;
 		time_armed = hrt_absolute_time();
+		init_complete = false;
 
 	} else if (!should_arm && mixer_servos_armed) {
 		/* armed but need to disarm */
 		up_pwm_servo_arm(false);
 		mixer_servos_armed = false;
+		init_complete = false;
 	}
 
 	if (mixer_servos_armed) {

src/modules/px4iofirmware/registers.c

@@ -268,7 +268,11 @@ registers_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num
 		/* copy channel data */
 		while ((offset < IO_SERVO_COUNT) && (num_values > 0)) {
 
-			if (*values > 1200)
+			if (*values == 0)
+				/* set to default */
+				r_page_servo_control_min[offset] = 900;
+
+			else if (*values > 1200)
 				r_page_servo_control_min[offset] = 1200;
 			else if (*values < 900)
 				r_page_servo_control_min[offset] = 900;
@@ -286,10 +290,14 @@ registers_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num
 		/* copy channel data */
 		while ((offset < IO_SERVO_COUNT) && (num_values > 0)) {
 
-			if (*values > 1200)
-				r_page_servo_control_max[offset] = 1200;
-			else if (*values < 900)
-				r_page_servo_control_max[offset] = 900;
+			if (*values == 0)
+				/* set to default */
+				r_page_servo_control_max[offset] = 2100;
+
+			else if (*values > 2100)
+				r_page_servo_control_max[offset] = 2100;
+			else if (*values < 1800)
+				r_page_servo_control_max[offset] = 1800;
 			else
 				r_page_servo_control_max[offset] = *values;