WebSVN - FlightCtrl - Diff - Rev 2102 and 2103 - /branches/dongfang_FC


#include <avr/io.h>
#include <avr/interrupt.h>
#include "eeprom.h"
#include "output.h"
#include "flight.h"
#include "attitude.h"
 
// #define COARSERESOLUTION 1
 
#ifdef COARSERESOLUTION
#define NEUTRAL_PULSELENGTH 938
#define STABILIZATION_LOG_DIVIDER 6
#define SERVOLIMIT 500
#define SCALE_FACTOR 4
#define CS2 ((1<<CS21)|(1<<CS20))
 
#else
#define NEUTRAL_PULSELENGTH 3750
#define STABILIZATION_LOG_DIVIDER 4
#define SERVOLIMIT 2000
#define SCALE_FACTOR 16
#define CS2 (1<<CS21)
#endif
 
#define MAX_SERVOS 8
#define FRAMELEN ((NEUTRAL_PULSELENGTH + SERVOLIMIT) * 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     PORTC |=  (1<<PORTC6)
#define HEF4017R_OFF    PORTC &= ~(1<<PORTC6)
 
/*****************************************************
 *              Initialize Timer 2
 *****************************************************/
void timer2_init(void) {
    uint8_t sreg = SREG;
 
    // disable all interrupts before reconfiguration
    cli();
 
    // set PD7 as output of the PWM for pitch servo
    DDRD |= (1 << DDD7);
    PORTD &= ~(1 << PORTD7); // set PD7 to low
 
    DDRC |= (1 << DDC6); // set PC6 as output (Reset for HEF4017)
    HEF4017R_ON; // enable reset
 
    // Timer/Counter 2 Control Register A
    // Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
    // PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)
    // PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)
    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.servoManualControl[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.servoConfigurations[axis].stabilizationFactor;
  value = value >> 8;
  if (staticParams.servoConfigurations[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.servoManualMaxSpeed;
  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.servoManualControl[axis] * SCALE_FACTOR);
  value += calculateStabilizedServoAxis(axis);
  int16_t limit = staticParams.servoConfigurations[axis].minValue * SCALE_FACTOR;
  if (value < limit) value = limit;
  limit = staticParams.servoConfigurations[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];
        value *= 2;
        servoValues[axis] = value + NEUTRAL_PULSELENGTH;
  }
  debugOut.analog[24] = servoValues[0];
  debugOut.analog[25] = servoValues[1];
  debugOut.analog[26] = servoValues[2];
  debugOut.analog[27] = servoValues[3];
}
 
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=0; axis<2; axis++) {
        value = featuredServoValue(axis);
        servoValues[axis + 4] = value;
  }
  for (axis=2; axis<MAX_SERVOS; axis++) {
        value = 128 * SCALE_FACTOR;
        servoValues[axis + 4] = 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 = FRAMELEN - 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/timer2.c - Rev 2102 → 2103

Rev 2102		Rev 2103
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		7
8	// #define COARSERESOLUTION 1	8	// #define COARSERESOLUTION 1
9		9
10	#ifdef COARSERESOLUTION	10	#ifdef COARSERESOLUTION
11	#define NEUTRAL_PULSELENGTH 938	11	#define NEUTRAL_PULSELENGTH 938
12	#define STABILIZATION_LOG_DIVIDER 6	12	#define STABILIZATION_LOG_DIVIDER 6
13	#define SERVOLIMIT 500	13	#define SERVOLIMIT 500
14	#define SCALE_FACTOR 4	14	#define SCALE_FACTOR 4
15	#define CS2 ((1<<CS21)\|(1<<CS20))	15	#define CS2 ((1<<CS21)\|(1<<CS20))
16		16
17	#else	17	#else
18	#define NEUTRAL_PULSELENGTH 3750	18	#define NEUTRAL_PULSELENGTH 3750
19	#define STABILIZATION_LOG_DIVIDER 4	19	#define STABILIZATION_LOG_DIVIDER 4
20	#define SERVOLIMIT 2000	20	#define SERVOLIMIT 2000
21	#define SCALE_FACTOR 16	21	#define SCALE_FACTOR 16
22	#define CS2 (1<<CS21)	22	#define CS2 (1<<CS21)
23	#endif	23	#endif
24		24
25	#define MAX_SERVOS 8	25	#define MAX_SERVOS 8
26	#define FRAMELEN ((NEUTRAL_PULSELENGTH + SERVOLIMIT) * staticParams.servoCount + 128)	26	#define FRAMELEN ((NEUTRAL_PULSELENGTH + SERVOLIMIT) * 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 PORTC \|= (1<<PORTC6)	34	#define HEF4017R_ON PORTC \|= (1<<PORTC6)
35	#define HEF4017R_OFF PORTC &= ~(1<<PORTC6)	35	#define HEF4017R_OFF PORTC &= ~(1<<PORTC6)
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 PWM for pitch servo
47	DDRD \|= (1 << DDD7);	47	DDRD \|= (1 << DDD7);
48	PORTD &= ~(1 << PORTD7); // set PD7 to low	48	PORTD &= ~(1 << PORTD7); // set PD7 to low
49		49
50	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)	50	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)
51	HEF4017R_ON; // enable reset	51	HEF4017R_ON; // enable reset
52		52
53	// Timer/Counter 2 Control Register A	53	// Timer/Counter 2 Control Register A
54	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)	54	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
55	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)	55	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)
56	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)	56	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)
57	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));	57	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));
58	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);	58	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);
59		59
60	// Timer/Counter 2 Control Register B	60	// Timer/Counter 2 Control Register B
61		61
62	// Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz	62	// Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz
63	// The timer increments from 0x00 to 0xFF with an update rate of 2.5 kHz or 0.4 us	63	// The timer increments from 0x00 to 0xFF with an update rate of 2.5 kHz or 0.4 us
64	// hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms	64	// hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms
65		65
66	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));	66	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));
67	TCCR2B \|= CS2;	67	TCCR2B \|= CS2;
68		68
69	// Initialize the Timer/Counter 2 Register	69	// Initialize the Timer/Counter 2 Register
70	TCNT2 = 0;	70	TCNT2 = 0;
71		71
72	// Initialize the Output Compare Register A used for signal generation on port PD7.	72	// Initialize the Output Compare Register A used for signal generation on port PD7.
73	OCR2A = 255;	73	OCR2A = 255;
74		74
75	// Timer/Counter 2 Interrupt Mask Register	75	// Timer/Counter 2 Interrupt Mask Register
76	// Enable timer output compare match A Interrupt only	76	// Enable timer output compare match A Interrupt only
77	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));	77	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));
78	TIMSK2 \|= (1 << OCIE2A);	78	TIMSK2 \|= (1 << OCIE2A);
79		79
80	for (uint8_t axis=0; axis<2; axis++)	80	for (uint8_t axis=0; axis<2; axis++)
81	previousManualValues[axis] = dynamicParams.servoManualControl[axis] * SCALE_FACTOR;	81	previousManualValues[axis] = dynamicParams.servoManualControl[axis] * SCALE_FACTOR;
82		82
83	SREG = sreg;	83	SREG = sreg;
84	}	84	}
85		85
86	/*****************************************************	86	/*****************************************************
87	* Control (camera gimbal etc.) servos	87	* Control (camera gimbal etc.) servos
88	*****************************************************/	88	*****************************************************/
89	int16_t calculateStabilizedServoAxis(uint8_t axis) {	89	int16_t calculateStabilizedServoAxis(uint8_t axis) {
90	int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about	90	int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about
91	// With full blast on stabilization gain (255) we want to convert a delta of, say, 125000 to 2000.	91	// With full blast on stabilization gain (255) we want to convert a delta of, say, 125000 to 2000.
92	// That is a divisor of about 1<<14. Same conclusion as H&I.	92	// That is a divisor of about 1<<14. Same conclusion as H&I.
93	value *= staticParams.servoConfigurations[axis].stabilizationFactor;	93	value *= staticParams.servoConfigurations[axis].stabilizationFactor;
94	value = value >> 8;	94	value = value >> 8;
95	if (staticParams.servoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)	95	if (staticParams.servoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)
96	return -value;	96	return -value;
97	return value;	97	return value;
98	}	98	}
99		99
100	// With constant-speed limitation.	100	// With constant-speed limitation.
101	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {	101	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {
102	int16_t diff = manualValue - previousManualValues[axis];	102	int16_t diff = manualValue - previousManualValues[axis];
103	uint8_t maxSpeed = staticParams.servoManualMaxSpeed;	103	uint8_t maxSpeed = staticParams.servoManualMaxSpeed;
104	if (diff > maxSpeed) diff = maxSpeed;	104	if (diff > maxSpeed) diff = maxSpeed;
105	else if (diff < -maxSpeed) diff = -maxSpeed;	105	else if (diff < -maxSpeed) diff = -maxSpeed;
106	manualValue = previousManualValues[axis] + diff;	106	manualValue = previousManualValues[axis] + diff;
107	previousManualValues[axis] = manualValue;	107	previousManualValues[axis] = manualValue;
108	return manualValue;	108	return manualValue;
109	}	109	}
110		110
111	// add stabilization and manual, apply soft position limits.	111	// add stabilization and manual, apply soft position limits.
112	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)	112	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)
113	int16_t featuredServoValue(uint8_t axis) {	113	int16_t featuredServoValue(uint8_t axis) {
114	int16_t value = calculateManualServoAxis(axis, dynamicParams.servoManualControl[axis] * SCALE_FACTOR);	114	int16_t value = calculateManualServoAxis(axis, dynamicParams.servoManualControl[axis] * SCALE_FACTOR);
115	value += calculateStabilizedServoAxis(axis);	115	value += calculateStabilizedServoAxis(axis);
116	int16_t limit = staticParams.servoConfigurations[axis].minValue * SCALE_FACTOR;	116	int16_t limit = staticParams.servoConfigurations[axis].minValue * SCALE_FACTOR;
117	if (value < limit) value = limit;	117	if (value < limit) value = limit;
118	limit = staticParams.servoConfigurations[axis].maxValue * SCALE_FACTOR;	118	limit = staticParams.servoConfigurations[axis].maxValue * SCALE_FACTOR;
119	if (value > limit) value = limit;	119	if (value > limit) value = limit;
120	value -= (128 * SCALE_FACTOR);	120	value -= (128 * SCALE_FACTOR);
121	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	121	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
122	else if (value > SERVOLIMIT) value = SERVOLIMIT;	122	else if (value > SERVOLIMIT) value = SERVOLIMIT;
123	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.	123	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.
124	return value + NEUTRAL_PULSELENGTH;	124	return value + NEUTRAL_PULSELENGTH;
125	}	125	}
126		126
127	void calculateControlServoValues(void) {	127	void calculateControlServoValues(void) {
128	int16_t value;	128	int16_t value;
129	for (uint8_t axis=0; axis<3; axis++) {	129	for (uint8_t axis=0; axis<4; axis++) {
130	value = controlServos[axis];	130	value = controlServos[axis];
131	value /= 2;	131	value *= 2;
132	servoValues[axis] = value + NEUTRAL_PULSELENGTH;	132	servoValues[axis] = value + NEUTRAL_PULSELENGTH;
133	}	133	}
134	debugOut.analog[18] = servoValues[0];	134	debugOut.analog[24] = servoValues[0];
-		135	debugOut.analog[25] = servoValues[1];
135	debugOut.analog[19] = servoValues[2];	136	debugOut.analog[26] = servoValues[2];
-		137	debugOut.analog[27] = servoValues[3];
136	}	138	}
137		139
138	void calculateFeaturedServoValues(void) {	140	void calculateFeaturedServoValues(void) {
139	int16_t value;	141	int16_t value;
140	uint8_t axis;	142	uint8_t axis;
141		143
142	// 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.
143	if (!recalculateServoTimes) return;	145	if (!recalculateServoTimes) return;
144		146
145	for (axis=0; axis<2; axis++) {	147	for (axis=0; axis<2; axis++) {
146	value = featuredServoValue(axis);	148	value = featuredServoValue(axis);
147	servoValues[axis + 3] = value;	149	servoValues[axis + 4] = value;
148	}	150	}
149	for (axis=2; axis<MAX_SERVOS; axis++) {	151	for (axis=2; axis<MAX_SERVOS; axis++) {
150	value = 128 * SCALE_FACTOR;	152	value = 128 * SCALE_FACTOR;
151	servoValues[axis + 3] = value;	153	servoValues[axis + 4] = value;
152	}	154	}
153		155
154	recalculateServoTimes = 0;	156	recalculateServoTimes = 0;
155	}	157	}
156		158
157	ISR(TIMER2_COMPA_vect) {	159	ISR(TIMER2_COMPA_vect) {
158	static uint16_t remainingPulseTime;	160	static uint16_t remainingPulseTime;
159	static uint8_t servoIndex = 0;	161	static uint8_t servoIndex = 0;
160	static uint16_t sumOfPulseTimes = 0;	162	static uint16_t sumOfPulseTimes = 0;
161		163
162	if (!remainingPulseTime) {	164	if (!remainingPulseTime) {
163	// 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.
164	if (servoIndex < staticParams.servoCount) {	166	if (servoIndex < staticParams.servoCount) {
165	// There are more signals to output.	167	// There are more signals to output.
166	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);	168	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);
167	servoIndex++;	169	servoIndex++;
168	} else {	170	} else {
169	// 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.
170	remainingPulseTime = FRAMELEN - sumOfPulseTimes;	172	remainingPulseTime = FRAMELEN - sumOfPulseTimes;
171	sumOfPulseTimes = servoIndex = 0;	173	sumOfPulseTimes = servoIndex = 0;
172	recalculateServoTimes = 1;	174	recalculateServoTimes = 1;
173	HEF4017R_ON;	175	HEF4017R_ON;
174	}	176	}
175	}	177	}
176		178
177	// 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.
178	if (remainingPulseTime > 256+128) {	180	if (remainingPulseTime > 256+128) {
179	// 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,
180	// 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.
181	OCR2A = 255;	183	OCR2A = 255;
182	TCCR2A &= ~(1<<COM2A0);	184	TCCR2A &= ~(1<<COM2A0);
183	remainingPulseTime-=256;	185	remainingPulseTime-=256;
184	} else if (remainingPulseTime > 256) {	186	} else if (remainingPulseTime > 256) {
185	// 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
186	// 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
187	// 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.
188	remainingPulseTime-=128;	190	remainingPulseTime-=128;
189	OCR2A=127;	191	OCR2A=127;
190	} else {	192	} else {
191	// 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
192	TCCR2A \|= (1<<COM2A0);	194	TCCR2A \|= (1<<COM2A0);
193	OCR2A = remainingPulseTime-1;	195	OCR2A = remainingPulseTime-1;
194	remainingPulseTime=0;	196	remainingPulseTime=0;
195	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.
196	}	198	}
197	}	199	}
198		200