WebSVN - FlightCtrl - Diff - Rev 2133 and 2135 - /branches/dongfang_FC_fixedwing/arduino


#include <avr/io.h>
#include <avr/interrupt.h>
#include "eeprom.h"
#include "output.h"
#include "flight.h"
#include "attitude.h"
#include "timer2.h"
 
// #define COARSERESOLUTION 1
 
#ifdef COARSERESOLUTION
#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/32000*1.5f + 0.5f))
#define STABILIZATION_LOG_DIVIDER 6
#define SERVOLIMIT ((int16_t)(F_CPU/32000*0.8f + 0.5f))
#define SCALE_FACTOR 4
#define CS2 ((1<<CS21)|(1<<CS20))
 
#else
#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/8000.0f * 1.5f + 0.5f))
#define STABILIZATION_LOG_DIVIDER 4
#define SERVOLIMIT ((int16_t)(F_CPU/8000.0f * 0.8f + 0.5f))
#define SCALE_FACTOR 16
#define CS2 (1<<CS21)
#endif
 
#define FRAMELENGTH ((uint16_t)(NEUTRAL_PULSELENGTH + SERVOLIMIT) * (uint16_t)staticParams.servoCount + 128)
#define MIN_PULSELENGTH (NEUTRAL_PULSELENGTH - SERVOLIMIT)
#define MAX_PULSELENGTH (NEUTRAL_PULSELENGTH + SERVOLIMIT)
 
volatile uint8_t recalculateServoTimes = 0;
volatile uint16_t servoValues[MAX_SERVOS];
volatile uint16_t previousManualValues[2];
 
#define HEF4017R_ON     PORTD |=  (1<<PORTD3)
#define HEF4017R_OFF    PORTD &= ~(1<<PORTD3)
 
/*****************************************************
 *              Initialize Timer 2
 *****************************************************/
void timer2_init(void) {
    uint8_t sreg = SREG;
 
    // disable all interrupts before reconfiguration
    cli();
 
    // set PD7 as output of the 4017 clk
    DDRB |= (1 << DDB3);
    PORTB &= ~(1 << PORTB3); // set PD7 to low
 
//  oc2b  DDRD |= (1 << DDD4); // set PC6 as output (Reset for HEF4017)
    DDRD |= (1 << DDD3); // set PC6 as output (Reset for HEF4017)
    HEF4017R_ON; // reset
 
    // Timer/Counter 2 Control Register A
    // Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
    // PD3: Output OCR2 match, (Bits: COM2B1 = 1, COM2B0 = 0)
    // PB3: Normal port operation, OC2A disconnected, (Bits: COM2A1 = 0, COM2A0 = 0)
    // ardu TCCR2A &= ~((1 << COM2B0) | (1 << COM2A1) | (1 << COM2A0) | (1 << WGM20) | (1 << WGM22));
    // ardu TCCR2A |= (1 << COM2B1) | (1 << WGM21);
    TCCR2A &= ~((1 << COM2A0) | (1 << COM2B1) | (1 << COM2B0) | (1 << WGM20) | (1 << WGM22));
    TCCR2A |= (1 << COM2A1) | (1 << WGM21);
 
    // Timer/Counter 2 Control Register B
 
    // Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz
    // The timer increments from 0x00 to 0xFF with an update rate of 2.5 kHz or 0.4 us
    // hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms
 
    TCCR2B &= ~((1 << FOC2A) | (1 << FOC2B) | (1 << CS20) | (1 << CS21) | (1 << CS22));
    TCCR2B |= CS2;
 
    // Initialize the Timer/Counter 2 Register
    TCNT2 = 0;
 
    // Initialize the Output Compare Register A used for signal generation on port PD7.
    OCR2A = 255;
 
    // Timer/Counter 2 Interrupt Mask Register
    // Enable timer output compare match A Interrupt only
    TIMSK2 &= ~((1 << OCIE2B) | (1 << TOIE2));
    TIMSK2 |= (1 << OCIE2A);
 
    for (uint8_t axis=0; axis<2; axis++)
      previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;
 
    SREG = sreg;
}
 
/*****************************************************
 * Control (camera gimbal etc.) servos
 *****************************************************/
int16_t calculateStabilizedServoAxis(uint8_t axis) {
  int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about
  // With full blast on stabilization gain (255) we want to convert a delta of, say, 125000 to 2000.
  // That is a divisor of about 1<<14. Same conclusion as H&I.
  value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;
  value = value >> 8;
  if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)
    return -value;
  return value;
}
 
// With constant-speed limitation.
uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {
  int16_t diff = manualValue - previousManualValues[axis];
  uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;
  if (diff > maxSpeed) diff = maxSpeed;
  else if (diff < -maxSpeed) diff = -maxSpeed;
  manualValue = previousManualValues[axis] + diff;
  previousManualValues[axis] = manualValue;
  return manualValue;
}
 
// add stabilization and manual, apply soft position limits.
// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)
int16_t featuredServoValue(uint8_t axis) {
  int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);
  value += calculateStabilizedServoAxis(axis);
  int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;
  if (value < limit) value = limit;
  limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;
  if (value > limit) value = limit;
  value -= (128 * SCALE_FACTOR);
  if (value < -SERVOLIMIT) value = -SERVOLIMIT;
  else if (value > SERVOLIMIT) value = SERVOLIMIT;
  // Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.
  return value + NEUTRAL_PULSELENGTH;
}
 
void calculateControlServoValues(void) {
  int16_t value;
  for (uint8_t axis=0; axis<4; axis++) {
        value = controlServos[axis];
        if (value < -SERVOLIMIT) value = -SERVOLIMIT;
    else if (value > SERVOLIMIT) value = SERVOLIMIT;
        servoValues[axis] = value + NEUTRAL_PULSELENGTH;
  }
}
 
void calculateFeaturedServoValues(void) {
  int16_t value;
  uint8_t axis;
 
  // Save the computation cost of computing a new value before the old one is used.
  if (!recalculateServoTimes) return;
 
  for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {
        value = featuredServoValue(axis-MAX_CONTROL_SERVOS);
        servoValues[axis] = value;
  }
  for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {
        value = 128 * SCALE_FACTOR;
        servoValues[axis] = value;
  }
 
  recalculateServoTimes = 0;
}
 
ISR(TIMER2_COMPA_vect) {
  static uint16_t remainingPulseTime;
  static uint8_t servoIndex = 0;
  static uint16_t sumOfPulseTimes = 0;
 
  if (!remainingPulseTime) {
    // Pulse is over, and the next pulse has already just started. Calculate length of next pulse.
    if (servoIndex < staticParams.servoCount) {
      // There are more signals to output.
      sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);
      servoIndex++;
    } else {
      // There are no more signals. Reset the counter and make this pulse cover the missing frame time.
      remainingPulseTime = FRAMELENGTH - sumOfPulseTimes;
      sumOfPulseTimes = servoIndex = 0;
      recalculateServoTimes = 1;
      HEF4017R_ON;
    }
  }
 
  // Schedule the next OCR2A event. The counter is already reset at this time.
  if (remainingPulseTime > 256+128) {
    // Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,
    // as long as it happens once per pulse. This will, because all pulses are > 255+128 long.
    OCR2A = 255;
    TCCR2A &= ~(1<<COM2A0);
    remainingPulseTime-=256;
  } else if (remainingPulseTime > 256) {
    // Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard
    // way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt
    // condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.
    remainingPulseTime-=128;
    OCR2A=127;
  } else {
    // Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low
    TCCR2A |= (1<<COM2A0);
    OCR2A = remainingPulseTime-1;
    remainingPulseTime=0;
    HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.
  }
}
 

Subversion Repositories FlightCtrl

(root)/branches/dongfang_FC_fixedwing/arduino_atmega328/timer2.c - Rev 2133 → 2135

Rev 2133		Rev 2135
1	#include <avr/io.h>	1	#include <avr/io.h>
2	#include <avr/interrupt.h>	2	#include <avr/interrupt.h>
3	#include "eeprom.h"	3	#include "eeprom.h"
4	#include "output.h"	4	#include "output.h"
5	#include "flight.h"	5	#include "flight.h"
6	#include "attitude.h"	6	#include "attitude.h"
7	#include "timer2.h"	7	#include "timer2.h"
8		8
9	// #define COARSERESOLUTION 1	9	// #define COARSERESOLUTION 1
10		10
11	#ifdef COARSERESOLUTION	11	#ifdef COARSERESOLUTION
12	#define NEUTRAL_PULSELENGTH 938	12	#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/32000*1.5f + 0.5f))
13	#define STABILIZATION_LOG_DIVIDER 6	13	#define STABILIZATION_LOG_DIVIDER 6
14	#define SERVOLIMIT 500	14	#define SERVOLIMIT ((int16_t)(F_CPU/32000*0.8f + 0.5f))
15	#define SCALE_FACTOR 4	15	#define SCALE_FACTOR 4
16	#define CS2 ((1<<CS21)\|(1<<CS20))	16	#define CS2 ((1<<CS21)\|(1<<CS20))
17		17
18	#else	18	#else
19	#define NEUTRAL_PULSELENGTH 3750	19	#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/8000.0f * 1.5f + 0.5f))
20	#define STABILIZATION_LOG_DIVIDER 4	20	#define STABILIZATION_LOG_DIVIDER 4
21	#define SERVOLIMIT 2000	21	#define SERVOLIMIT ((int16_t)(F_CPU/8000.0f * 0.8f + 0.5f))
22	#define SCALE_FACTOR 16	22	#define SCALE_FACTOR 16
23	#define CS2 (1<<CS21)	23	#define CS2 (1<<CS21)
24	#endif	24	#endif
25		25
26	#define FRAMELEN ((NEUTRAL_PULSELENGTH + SERVOLIMIT) * staticParams.servoCount + 128)	26	#define FRAMELENGTH ((uint16_t)(NEUTRAL_PULSELENGTH + SERVOLIMIT) * (uint16_t)staticParams.servoCount + 128)
27	#define MIN_PULSELENGTH (NEUTRAL_PULSELENGTH - SERVOLIMIT)	27	#define MIN_PULSELENGTH (NEUTRAL_PULSELENGTH - SERVOLIMIT)
28	#define MAX_PULSELENGTH (NEUTRAL_PULSELENGTH + SERVOLIMIT)	28	#define MAX_PULSELENGTH (NEUTRAL_PULSELENGTH + SERVOLIMIT)
29		29
30	volatile uint8_t recalculateServoTimes = 0;	30	volatile uint8_t recalculateServoTimes = 0;
31	volatile uint16_t servoValues[MAX_SERVOS];	31	volatile uint16_t servoValues[MAX_SERVOS];
32	volatile uint16_t previousManualValues[2];	32	volatile uint16_t previousManualValues[2];
33		33
34	#define HEF4017R_ON PORTD \|= (1<<PORTD3)	34	#define HEF4017R_ON PORTD \|= (1<<PORTD3)
35	#define HEF4017R_OFF PORTD &= ~(1<<PORTD3)	35	#define HEF4017R_OFF PORTD &= ~(1<<PORTD3)
36		36
37	/*****************************************************	37	/*****************************************************
38	* Initialize Timer 2	38	* Initialize Timer 2
39	*****************************************************/	39	*****************************************************/
40	void timer2_init(void) {	40	void timer2_init(void) {
41	uint8_t sreg = SREG;	41	uint8_t sreg = SREG;
42		42
43	// disable all interrupts before reconfiguration	43	// disable all interrupts before reconfiguration
44	cli();	44	cli();
45		45
46	// set PD7 as output of the PWM for pitch servo	46	// set PD7 as output of the 4017 clk
47	DDRB \|= (1 << DDB3);	47	DDRB \|= (1 << DDB3);
48	PORTB &= ~(1 << PORTB3); // set PD7 to low	48	PORTB &= ~(1 << PORTB3); // set PD7 to low
49		49
50	// oc2b DDRD \|= (1 << DDD4); // set PC6 as output (Reset for HEF4017)	50	// oc2b DDRD \|= (1 << DDD4); // set PC6 as output (Reset for HEF4017)
51	DDRD \|= (1 << DDD3); // set PC6 as output (Reset for HEF4017)	51	DDRD \|= (1 << DDD3); // set PC6 as output (Reset for HEF4017)
52	HEF4017R_ON; // reset	52	HEF4017R_ON; // reset
53		53
54	// Timer/Counter 2 Control Register A	54	// Timer/Counter 2 Control Register A
55	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)	55	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
56	// PD3: Output OCR2 match, (Bits: COM2B1 = 1, COM2B0 = 0)	56	// PD3: Output OCR2 match, (Bits: COM2B1 = 1, COM2B0 = 0)
57	// PB3: Normal port operation, OC2A disconnected, (Bits: COM2A1 = 0, COM2A0 = 0)	57	// PB3: Normal port operation, OC2A disconnected, (Bits: COM2A1 = 0, COM2A0 = 0)
58	// ardu TCCR2A &= ~((1 << COM2B0) \| (1 << COM2A1) \| (1 << COM2A0) \| (1 << WGM20) \| (1 << WGM22));	58	// ardu TCCR2A &= ~((1 << COM2B0) \| (1 << COM2A1) \| (1 << COM2A0) \| (1 << WGM20) \| (1 << WGM22));
59	// ardu TCCR2A \|= (1 << COM2B1) \| (1 << WGM21);	59	// ardu TCCR2A \|= (1 << COM2B1) \| (1 << WGM21);
60	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));	60	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));
61	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);	61	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);
62		62
63	// Timer/Counter 2 Control Register B	63	// Timer/Counter 2 Control Register B
64		64
65	// Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz	65	// Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz
66	// The timer increments from 0x00 to 0xFF with an update rate of 2.5 kHz or 0.4 us	66	// The timer increments from 0x00 to 0xFF with an update rate of 2.5 kHz or 0.4 us
67	// hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms	67	// hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms
68		68
69	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));	69	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));
70	TCCR2B \|= CS2;	70	TCCR2B \|= CS2;
71		71
72	// Initialize the Timer/Counter 2 Register	72	// Initialize the Timer/Counter 2 Register
73	TCNT2 = 0;	73	TCNT2 = 0;
74		74
75	// Initialize the Output Compare Register A used for signal generation on port PD7.	75	// Initialize the Output Compare Register A used for signal generation on port PD7.
76	OCR2A = 255;	76	OCR2A = 255;
77		77
78	// Timer/Counter 2 Interrupt Mask Register	78	// Timer/Counter 2 Interrupt Mask Register
79	// Enable timer output compare match A Interrupt only	79	// Enable timer output compare match A Interrupt only
80	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));	80	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));
81	TIMSK2 \|= (1 << OCIE2A);	81	TIMSK2 \|= (1 << OCIE2A);
82		82
83	for (uint8_t axis=0; axis<2; axis++)	83	for (uint8_t axis=0; axis<2; axis++)
84	previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;	84	previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;
85		85
86	SREG = sreg;	86	SREG = sreg;
87	}	87	}
88		88
89	/*****************************************************	89	/*****************************************************
90	* Control (camera gimbal etc.) servos	90	* Control (camera gimbal etc.) servos
91	*****************************************************/	91	*****************************************************/
92	int16_t calculateStabilizedServoAxis(uint8_t axis) {	92	int16_t calculateStabilizedServoAxis(uint8_t axis) {
93	int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about	93	int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about
94	// With full blast on stabilization gain (255) we want to convert a delta of, say, 125000 to 2000.	94	// With full blast on stabilization gain (255) we want to convert a delta of, say, 125000 to 2000.
95	// That is a divisor of about 1<<14. Same conclusion as H&I.	95	// That is a divisor of about 1<<14. Same conclusion as H&I.
96	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;	96	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;
97	value = value >> 8;	97	value = value >> 8;
98	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)	98	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)
99	return -value;	99	return -value;
100	return value;	100	return value;
101	}	101	}
102		102
103	// With constant-speed limitation.	103	// With constant-speed limitation.
104	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {	104	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {
105	int16_t diff = manualValue - previousManualValues[axis];	105	int16_t diff = manualValue - previousManualValues[axis];
106	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;	106	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;
107	if (diff > maxSpeed) diff = maxSpeed;	107	if (diff > maxSpeed) diff = maxSpeed;
108	else if (diff < -maxSpeed) diff = -maxSpeed;	108	else if (diff < -maxSpeed) diff = -maxSpeed;
109	manualValue = previousManualValues[axis] + diff;	109	manualValue = previousManualValues[axis] + diff;
110	previousManualValues[axis] = manualValue;	110	previousManualValues[axis] = manualValue;
111	return manualValue;	111	return manualValue;
112	}	112	}
113		113
114	// add stabilization and manual, apply soft position limits.	114	// add stabilization and manual, apply soft position limits.
115	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)	115	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)
116	int16_t featuredServoValue(uint8_t axis) {	116	int16_t featuredServoValue(uint8_t axis) {
117	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);	117	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);
118	value += calculateStabilizedServoAxis(axis);	118	value += calculateStabilizedServoAxis(axis);
119	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;	119	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;
120	if (value < limit) value = limit;	120	if (value < limit) value = limit;
121	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;	121	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;
122	if (value > limit) value = limit;	122	if (value > limit) value = limit;
123	value -= (128 * SCALE_FACTOR);	123	value -= (128 * SCALE_FACTOR);
124	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	124	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
125	else if (value > SERVOLIMIT) value = SERVOLIMIT;	125	else if (value > SERVOLIMIT) value = SERVOLIMIT;
126	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.	126	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.
127	return value + NEUTRAL_PULSELENGTH;	127	return value + NEUTRAL_PULSELENGTH;
128	}	128	}
129		129
130	void calculateControlServoValues(void) {	130	void calculateControlServoValues(void) {
131	int16_t value;	131	int16_t value;
132	for (uint8_t axis=0; axis<4; axis++) {	132	for (uint8_t axis=0; axis<4; axis++) {
133	value = controlServos[axis];	133	value = controlServos[axis];
134	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	134	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
135	else if (value > SERVOLIMIT) value = SERVOLIMIT;	135	else if (value > SERVOLIMIT) value = SERVOLIMIT;
136	servoValues[axis] = value + NEUTRAL_PULSELENGTH;	136	servoValues[axis] = value + NEUTRAL_PULSELENGTH;
137	}	137	}
138	}	138	}
139		139
140	void calculateFeaturedServoValues(void) {	140	void calculateFeaturedServoValues(void) {
141	int16_t value;	141	int16_t value;
142	uint8_t axis;	142	uint8_t axis;
143		143
144	// Save the computation cost of computing a new value before the old one is used.	144	// Save the computation cost of computing a new value before the old one is used.
145	if (!recalculateServoTimes) return;	145	if (!recalculateServoTimes) return;
146		146
147	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {	147	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {
148	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);	148	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);
149	servoValues[axis] = value;	149	servoValues[axis] = value;
150	}	150	}
151	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {	151	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {
152	value = 128 * SCALE_FACTOR;	152	value = 128 * SCALE_FACTOR;
153	servoValues[axis] = value;	153	servoValues[axis] = value;
154	}	154	}
155		155
156	recalculateServoTimes = 0;	156	recalculateServoTimes = 0;
157	}	157	}
158		158
159	ISR(TIMER2_COMPA_vect) {	159	ISR(TIMER2_COMPA_vect) {
160	static uint16_t remainingPulseTime;	160	static uint16_t remainingPulseTime;
161	static uint8_t servoIndex = 0;	161	static uint8_t servoIndex = 0;
162	static uint16_t sumOfPulseTimes = 0;	162	static uint16_t sumOfPulseTimes = 0;
163		163
164	if (!remainingPulseTime) {	164	if (!remainingPulseTime) {
165	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.	165	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.
166	if (servoIndex < staticParams.servoCount) {	166	if (servoIndex < staticParams.servoCount) {
167	// There are more signals to output.	167	// There are more signals to output.
168	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);	168	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);
169	servoIndex++;	169	servoIndex++;
170	} else {	170	} else {
171	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.	171	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.
172	remainingPulseTime = FRAMELEN - sumOfPulseTimes;	172	remainingPulseTime = FRAMELENGTH - sumOfPulseTimes;
173	sumOfPulseTimes = servoIndex = 0;	173	sumOfPulseTimes = servoIndex = 0;
174	recalculateServoTimes = 1;	174	recalculateServoTimes = 1;
175	HEF4017R_ON;	175	HEF4017R_ON;
176	}	176	}
177	}	177	}
178		178
179	// Schedule the next OCR2A event. The counter is already reset at this time.	179	// Schedule the next OCR2A event. The counter is already reset at this time.
180	if (remainingPulseTime > 256+128) {	180	if (remainingPulseTime > 256+128) {
181	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,	181	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,
182	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.	182	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.
183	OCR2A = 255;	183	OCR2A = 255;
184	TCCR2A &= ~(1<<COM2A0);	184	TCCR2A &= ~(1<<COM2A0);
185	remainingPulseTime-=256;	185	remainingPulseTime-=256;
186	} else if (remainingPulseTime > 256) {	186	} else if (remainingPulseTime > 256) {
187	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard	187	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard
188	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt	188	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt
189	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.	189	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.
190	remainingPulseTime-=128;	190	remainingPulseTime-=128;
191	OCR2A=127;	191	OCR2A=127;
192	} else {	192	} else {
193	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low	193	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low
194	TCCR2A \|= (1<<COM2A0);	194	TCCR2A \|= (1<<COM2A0);
195	OCR2A = remainingPulseTime-1;	195	OCR2A = remainingPulseTime-1;
196	remainingPulseTime=0;	196	remainingPulseTime=0;
197	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.	197	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.
198	}	198	}
199	}	199	}
200		200