WebSVN - FlightCtrl - Diff - Rev 2125 and 2135 - /branches/dongfang_FC


#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     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; // 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.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;
  //int16_t minLimit = staticParams.controlServoMinValue * SCALE_FACTOR;
  //int16_t maxLimit = staticParams.controlServoMaxValue * SCALE_FACTOR;
  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/timer2.c @ 2088 - Rev 2125 → 2135

Rev 2125		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 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		-
37	//#define HEF4017R_ON ;	-
38	//#define HEF4017R_OFF ;	-
39		36
40	/*****************************************************	37	/*****************************************************
41	* Initialize Timer 2	38	* Initialize Timer 2
42	*****************************************************/	39	*****************************************************/
43	void timer2_init(void) {	40	void timer2_init(void) {
44	uint8_t sreg = SREG;	41	uint8_t sreg = SREG;
45		42
46	// disable all interrupts before reconfiguration	43	// disable all interrupts before reconfiguration
47	cli();	44	cli();
48		45
49	// set PD7 as output of the PWM for pitch servo	46	// set PD7 as output of the PWM for pitch servo
50	DDRD \|= (1 << DDD7);	47	DDRD \|= (1 << DDD7);
51	PORTD &= ~(1 << PORTD7); // set PD7 to low	48	PORTD &= ~(1 << PORTD7); // set PD7 to low
52		49
53	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)	50	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)
54	HEF4017R_ON; // reset	51	HEF4017R_ON; // reset
55		52
56	// Timer/Counter 2 Control Register A	53	// Timer/Counter 2 Control Register A
57	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)	54	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
58	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)	55	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)
59	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)	56	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)
60	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));	57	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));
61	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);	58	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);
62		59
63	// Timer/Counter 2 Control Register B	60	// Timer/Counter 2 Control Register B
64		61
65	// 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
66	// 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
67	// 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
68		65
69	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));	66	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));
70	TCCR2B \|= CS2;	67	TCCR2B \|= CS2;
71		68
72	// Initialize the Timer/Counter 2 Register	69	// Initialize the Timer/Counter 2 Register
73	TCNT2 = 0;	70	TCNT2 = 0;
74		71
75	// 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.
76	OCR2A = 255;	73	OCR2A = 255;
77		74
78	// Timer/Counter 2 Interrupt Mask Register	75	// Timer/Counter 2 Interrupt Mask Register
79	// Enable timer output compare match A Interrupt only	76	// Enable timer output compare match A Interrupt only
80	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));	77	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));
81	TIMSK2 \|= (1 << OCIE2A);	78	TIMSK2 \|= (1 << OCIE2A);
82		79
83	for (uint8_t axis=0; axis<2; axis++)	80	for (uint8_t axis=0; axis<2; axis++)
84	previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;	81	previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;
85		82
86	SREG = sreg;	83	SREG = sreg;
87	}	84	}
88		85
89	/*****************************************************	86	/*****************************************************
90	* Control (camera gimbal etc.) servos	87	* Control (camera gimbal etc.) servos
91	*****************************************************/	88	*****************************************************/
92	int16_t calculateStabilizedServoAxis(uint8_t axis) {	89	int16_t calculateStabilizedServoAxis(uint8_t axis) {
93	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
94	// 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.
95	// 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.
96	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;	93	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;
97	value = value >> 8;	94	value = value >> 8;
98	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)	95	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)
99	return -value;	96	return -value;
100	return value;	97	return value;
101	}	98	}
102		99
103	// With constant-speed limitation.	100	// With constant-speed limitation.
104	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {	101	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {
105	int16_t diff = manualValue - previousManualValues[axis];	102	int16_t diff = manualValue - previousManualValues[axis];
106	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;	103	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;
107	if (diff > maxSpeed) diff = maxSpeed;	104	if (diff > maxSpeed) diff = maxSpeed;
108	else if (diff < -maxSpeed) diff = -maxSpeed;	105	else if (diff < -maxSpeed) diff = -maxSpeed;
109	manualValue = previousManualValues[axis] + diff;	106	manualValue = previousManualValues[axis] + diff;
110	previousManualValues[axis] = manualValue;	107	previousManualValues[axis] = manualValue;
111	return manualValue;	108	return manualValue;
112	}	109	}
113		110
114	// add stabilization and manual, apply soft position limits.	111	// add stabilization and manual, apply soft position limits.
115	// 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)
116	int16_t featuredServoValue(uint8_t axis) {	113	int16_t featuredServoValue(uint8_t axis) {
117	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);	114	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);
118	value += calculateStabilizedServoAxis(axis);	115	value += calculateStabilizedServoAxis(axis);
119	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;	116	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;
120	if (value < limit) value = limit;	117	if (value < limit) value = limit;
121	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;	118	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;
122	if (value > limit) value = limit;	119	if (value > limit) value = limit;
123	value -= (128 * SCALE_FACTOR);	120	value -= (128 * SCALE_FACTOR);
124	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	121	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
125	else if (value > SERVOLIMIT) value = SERVOLIMIT;	122	else if (value > SERVOLIMIT) value = SERVOLIMIT;
126	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.	123	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.
127	return value + NEUTRAL_PULSELENGTH;	124	return value + NEUTRAL_PULSELENGTH;
128	}	125	}
129		126
130	void calculateControlServoValues(void) {	127	void calculateControlServoValues(void) {
131	int16_t value;	128	int16_t value;
132	//int16_t minLimit = staticParams.controlServoMinValue * SCALE_FACTOR;	129	//int16_t minLimit = staticParams.controlServoMinValue * SCALE_FACTOR;
133	//int16_t maxLimit = staticParams.controlServoMaxValue * SCALE_FACTOR;	130	//int16_t maxLimit = staticParams.controlServoMaxValue * SCALE_FACTOR;
134	for (uint8_t axis=0; axis<4; axis++) {	131	for (uint8_t axis=0; axis<4; axis++) {
135	value = controlServos[axis];	132	value = controlServos[axis];
136	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	133	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
137	else if (value > SERVOLIMIT) value = SERVOLIMIT;	134	else if (value > SERVOLIMIT) value = SERVOLIMIT;
138	servoValues[axis] = value + NEUTRAL_PULSELENGTH;	135	servoValues[axis] = value + NEUTRAL_PULSELENGTH;
139	}	136	}
140	}	137	}
141		138
142	void calculateFeaturedServoValues(void) {	139	void calculateFeaturedServoValues(void) {
143	int16_t value;	140	int16_t value;
144	uint8_t axis;	141	uint8_t axis;
145		142
146	// Save the computation cost of computing a new value before the old one is used.	143	// Save the computation cost of computing a new value before the old one is used.
147	if (!recalculateServoTimes) return;	144	if (!recalculateServoTimes) return;
148		145
149	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {	146	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {
150	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);	147	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);
151	servoValues[axis] = value;	148	servoValues[axis] = value;
152	}	149	}
153	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {	150	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {
154	value = 128 * SCALE_FACTOR;	151	value = 128 * SCALE_FACTOR;
155	servoValues[axis] = value;	152	servoValues[axis] = value;
156	}	153	}
157		154
158	recalculateServoTimes = 0;	155	recalculateServoTimes = 0;
159	}	156	}
160		157
161	ISR(TIMER2_COMPA_vect) {	158	ISR(TIMER2_COMPA_vect) {
162	static uint16_t remainingPulseTime;	159	static uint16_t remainingPulseTime;
163	static uint8_t servoIndex = 0;	160	static uint8_t servoIndex = 0;
164	static uint16_t sumOfPulseTimes = 0;	161	static uint16_t sumOfPulseTimes = 0;
165		162
166	if (!remainingPulseTime) {	163	if (!remainingPulseTime) {
167	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.	164	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.
168	if (servoIndex < staticParams.servoCount) {	165	if (servoIndex < staticParams.servoCount) {
169	// There are more signals to output.	166	// There are more signals to output.
170	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);	167	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);
171	servoIndex++;	168	servoIndex++;
172	} else {	169	} else {
173	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.	170	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.
174	remainingPulseTime = FRAMELEN - sumOfPulseTimes;	171	remainingPulseTime = FRAMELENGTH - sumOfPulseTimes;
175	sumOfPulseTimes = servoIndex = 0;	172	sumOfPulseTimes = servoIndex = 0;
176	recalculateServoTimes = 1;	173	recalculateServoTimes = 1;
177	HEF4017R_ON;	174	HEF4017R_ON;
178	}	175	}
179	}	176	}
180		177
181	// Schedule the next OCR2A event. The counter is already reset at this time.	178	// Schedule the next OCR2A event. The counter is already reset at this time.
182	if (remainingPulseTime > 256+128) {	179	if (remainingPulseTime > 256+128) {
183	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,	180	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,
184	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.	181	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.
185	OCR2A = 255;	182	OCR2A = 255;
186	TCCR2A &= ~(1<<COM2A0);	183	TCCR2A &= ~(1<<COM2A0);
187	remainingPulseTime-=256;	184	remainingPulseTime-=256;
188	} else if (remainingPulseTime > 256) {	185	} else if (remainingPulseTime > 256) {
189	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard	186	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard
190	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt	187	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt
191	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.	188	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.
192	remainingPulseTime-=128;	189	remainingPulseTime-=128;
193	OCR2A=127;	190	OCR2A=127;
194	} else {	191	} else {
195	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low	192	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low
196	TCCR2A \|= (1<<COM2A0);	193	TCCR2A \|= (1<<COM2A0);
197	OCR2A = remainingPulseTime-1;	194	OCR2A = remainingPulseTime-1;
198	remainingPulseTime=0;	195	remainingPulseTime=0;
199	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.	196	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.
200	}	197	}
201	}	198	}
202		199