ArduPPM V2.3.13

- New interrupt system that handles certain Futaba receivers better (simultaneous changes on groups of R/C channels in fast intervals)
- Improved active channel detection requering 100 valid pulses before channel is marked active

- Removed forced throttle fail-safe after channel loss
- Lost channel detection signal for APM by setting channel output to 800us (not activated yet, need APM code to handle signals)

Tools/ArduPPM/Libraries/PPM_Encoder.h

@@ -1,5 +1,5 @@
 // -------------------------------------------------------------
-// ArduPPM (PPM Encoder) V2.3.12
+// ArduPPM (PPM Encoder) V2.3.13
 // -------------------------------------------------------------
 // Improved servo to ppm for ArduPilot MEGA v1.x (ATmega328p),
 // PhoneDrone and APM2.x (ATmega32u2)
@@ -27,11 +27,10 @@
 // -----------------------
 // - PPM output will not be enabled unless a input signal has been detected and verified
 // - Verified inputs are lost during operaton (lose servo wire or receiver malfunction):
-//   + The PPM output channel for the lost input will be set to the default fail-safe value
-//   + PPM throttle output (ch3) will be permanently set to fail-safe (900us)
+//   + The last known value of the lost input channel is keept for ~1 second
+//   + If the lost input channel is not restored within ~1 second, it will be set to the default fail-safe value
 // - Lost channel signal is restored:
-//   + PPM output for the restored channel will be updated with the valid signal
-//   + PPM throttle output (ch3) will not be restored, and will continue to output fail-safe (900us)
+//   + Normal channel operation is restored using the valid input signal
 
 // PPM PASS-THROUGH MODE (signal pin 2&3 shorted):
 // -----------------------------------------------
@@ -118,6 +117,16 @@
 //         - Improved LED status for APM 2.x
 //         - Improved jitter performance (PPM output using nested interrupts)
 
+// 30-11-2012
+// V2.3.13pre - Internal dev only pre-release
+//            - Improved active channel detection requering 100 valid pulses before channel is marked active
+//            - Removed forced throttle fail-safe after channel loss
+//            - Changed fail-safe values to 800us, this will be used by APM code to detect channel loss and decide fail safe actions
+
+// 16-12-2012
+// V2.3.13 - Official release
+//         - Fail-safe vales changed back to normal fail-safe values. Use until APM code knows how to handle lost channel signal (800us)
+
 // -------------------------------------------------------------
 
 #ifndef _PPM_ENCODER_H_
@@ -159,7 +168,7 @@
 #endif
 
 // Version stamp for firmware hex file ( decode hex file using <avr-objdump -s file.hex> and look for "ArduPPM" string )
-const char ver[15] = "ArduPPMv2.3.12"; 
+const char ver[15] = "ArduPPMv2.3.13"; 
 
 // -------------------------------------------------------------
 // INPUT MODE
@@ -173,6 +182,15 @@ const char ver[15] = "ArduPPMv2.3.12";
 
 // Servo input mode (jumper (default), pwm, ppm, jeti or spektrum)
 volatile uint8_t servo_input_mode = JUMPER_SELECT_MODE;
+
+// -------------------------------------------------------------
+// FAILSAFE MODE
+// -------------------------------------------------------------
+
+//#define _APM_FAILSAFE_   // Used to spesify APM 800us channel loss fail safe values, remove to use normal fail safe values (stand alone encoder board)
+
+// -------------------------------------------------------------
+// SERVO LIMIT VALUES
 // -------------------------------------------------------------
 
 // Number of Timer1 ticks in one microsecond
@@ -181,11 +199,6 @@ volatile uint8_t servo_input_mode = JUMPER_SELECT_MODE;
 // 400us PPM pre pulse
 #define PPM_PRE_PULSE         ONE_US * 400
 
-
-// -------------------------------------------------------------
-// SERVO LIMIT VALUES
-// -------------------------------------------------------------
-
 // Servo minimum position
 #define PPM_SERVO_MIN         ONE_US * 900 - PPM_PRE_PULSE
 
@@ -201,6 +214,9 @@ volatile uint8_t servo_input_mode = JUMPER_SELECT_MODE;
 // Throttle during failsafe
 #define PPM_THROTTLE_FAILSAFE ONE_US * 900 - PPM_PRE_PULSE
 
+// Channel loss failsafe
+#define PPM_CHANNEL_LOSS ONE_US * 800 - PPM_PRE_PULSE
+
 // CH5 power on values (mode selection channel)
 #define PPM_CH5_MODE_4        ONE_US * 1555 - PPM_PRE_PULSE
 
@@ -219,6 +235,32 @@ volatile uint8_t servo_input_mode = JUMPER_SELECT_MODE;
 // Size of ppm[..] data array ( servo channels * 2 + 2)
 #define PPM_ARRAY_MAX         18
 
+#ifdef _APM_FAILSAFE_
+// -------------------------------------------------------------
+// APM FAILSAFE VALUES
+// -------------------------------------------------------------
+volatile uint16_t failsafe_ppm[ PPM_ARRAY_MAX ] =                               
+{
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 1
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 2
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 3 (throttle)
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 4
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 5
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 6
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 7
+    PPM_PRE_PULSE,
+    PPM_CHANNEL_LOSS,         // Channel 8
+    PPM_PRE_PULSE,
+    PPM_PERIOD
+};
+#else
 // -------------------------------------------------------------
 // SERVO FAILSAFE VALUES
 // -------------------------------------------------------------
@@ -243,6 +285,7 @@ volatile uint16_t failsafe_ppm[ PPM_ARRAY_MAX ] =
     PPM_PRE_PULSE,
     PPM_PERIOD
 };
+#endif
 
 // -------------------------------------------------------------
 // Data array for storing ppm (8 channels) pulse widths.
@@ -275,8 +318,9 @@ volatile uint16_t ppm[ PPM_ARRAY_MAX ] =
 #define PPM_TIMEOUT_VALUE 40 // ~1sec before triggering missing channel detection
 volatile uint8_t ppm_timeout[ PPM_ARRAY_MAX ];
 
-// Servo input channel connected flag
-volatile bool servo_input_connected[ PPM_ARRAY_MAX ];
+// Servo input channel connected status
+#define SERVO_INPUT_CONNECTED_VALUE 100
+volatile uint8_t servo_input_connected[ PPM_ARRAY_MAX ];
 
 // AVR parameters for PhoneDrone and APM2 boards using ATmega32u2
 #if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
@@ -300,7 +344,7 @@ volatile bool servo_input_connected[ PPM_ARRAY_MAX ];
 #define PPM_COMPARE_FORCE_MATCH    FOC1A
 
 #define    USB_DDR            DDRC
-#define USB_PORT              PORTC
+#define    USB_PORT           PORTC
 #define    USB_PIN            PC2
 
 // true if we have received a USB device connect event
@@ -356,10 +400,7 @@ void EVENT_USB_Device_Disconnect(void)
 #else
 #error NO SUPPORTED DEVICE FOUND! (ATmega16u2 / ATmega32u2 / ATmega328p)
 #endif
-
-// Used to force throttle fail-safe mode (RTL)
-volatile bool throttle_failsafe_force = false;
-
+    
 // Used to indicate invalid SERVO input signals
 volatile uint8_t servo_input_errors = 0;
 
@@ -462,9 +503,9 @@ ISR( WDT_vect ) // If watchdog is triggered then enable missing signal flag and
     if ( ppm_generator_active || brownout_reset )
     {
         // Copy failsafe values to ppm[..]
-        for( volatile uint8_t i = 0; i < PPM_ARRAY_MAX; i++ )
+        for( uint8_t i = 0; i < PPM_ARRAY_MAX; i++ )
         {
-            ppm[ i ] = failsafe_ppm[ i ];
+			ppm[ i ] = failsafe_ppm[ i ];
         }
     }
 
@@ -568,7 +609,7 @@ ISR( SERVO_INT_VECTOR )
     // SERVO PWM MODE
     // ------------------------------------------------------------------------------
 
-CHECK_PINS_START: // Start of servo input check
+//CHECK_PINS_START: // Start of servo input check
 
     // Store current servo input pins
     servo_pins = SERVO_INPUT;
@@ -608,27 +649,15 @@ CHECK_PINS_LOOP: // Input servo pin check loop
             // Set servo input missing flag false to indicate that we have received servo input signals
             servo_input_missing = false;
             
-            // Channel has received a valid signal, so it must be connected
-            servo_input_connected [ ppm_channel ] = true;
-            
-           //Reset ppm single channel fail-safe timeout
-            ppm_timeout[ ppm_channel ] = 0;
-
-            // Check for forced throttle fail-safe
-            if( throttle_failsafe_force )
+            // Count valid signals to mark channel active
+            if( servo_input_connected[ ppm_channel ] < SERVO_INPUT_CONNECTED_VALUE )
             {
-                if( ppm_channel == 5 )
-                {
-                    // Force throttle fail-safe
-                    servo_width = PPM_THROTTLE_FAILSAFE;
-                }
-
-            #if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
-                // Turn on RX LED if throttle fail-safe is forced
-                PORTD &= ~(1 << PD4);
-            #endif    
+                servo_input_connected[ ppm_channel ]++;
             }
             
+           //Reset ppm single channel fail-safe timeout
+            ppm_timeout[ ppm_channel ] = 0;
+    
         #ifdef _AVERAGE_FILTER_
             // Average filter to smooth input jitter
             servo_width += ppm[ ppm_channel ];
@@ -724,25 +753,26 @@ ISR( PPM_INT_VECTOR, ISR_NOBLOCK )
         cli();
         PPM_COMPARE += failsafe_ppm[ ppm_out_channel ];
         sei();
-        
-        // Did we lose an active servo input channel? If so force throttle fail-safe (RTL)
-        if( servo_input_connected[ ppm_out_channel ] )
-        {
-            throttle_failsafe_force = true;
-        }
+
+    #if defined (__AVR_ATmega16U2__) || defined (__AVR_ATmega32U2__)
+        // Turn on RX LED to indicate a fail-safe condition
+        PORTD &= ~(1 << PD4);
+    #endif    
     }
     else
     {
         // Use latest ppm input value   
         cli();
         PPM_COMPARE += ppm[ ppm_out_channel ];
-        sei();
+		sei();
         
-        // Increment channel timeout (reset to zero in input interrupt each time a valid signal is detected)
-        ppm_timeout[ ppm_out_channel ] ++;
+        // Increment active channel timeout (reset to zero in input interrupt each time a valid signal is detected)
+        if( servo_input_connected[ ppm_out_channel ] >= SERVO_INPUT_CONNECTED_VALUE )
+        {
+            ppm_timeout[ ppm_out_channel ]++;
+        }
     }
-    
-    // Select the next ppm channel
+
     if( ++ppm_out_channel >= PPM_ARRAY_MAX ) 
     {
         ppm_out_channel = 0;