WebSVN - FlightCtrl - Diff - Rev 2135 and 2142 - /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 SERVO_NORMAL_LIMIT ((int16_t)(F_CPU/32000*0.5f + 0.5f))
#define SERVO_ABS_LIMIT ((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 SERVO_NORMAL_LIMIT ((int16_t)(F_CPU/8000.0f * 0.5f + 0.5f))
#define SERVO_ABS_LIMIT ((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 + SERVO_ABS_LIMIT) * (uint16_t)staticParams.servoCount + 128)
 
volatile uint16_t servoValues[MAX_SERVOS];
//volatile uint8_t recalculateServoTimes = 0;
//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 i=0; i<MAX_SERVOS; i++)
        servoValues[i] = NEUTRAL_PULSELENGTH;
 
    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];
 
        // Apply configurable limits. These are signed: +-128 is twice the normal +- 0.5 ms limit and +- 64 is normal.
        int16_t min = (staticParams.servos[axis].minValue * SERVO_NORMAL_LIMIT) >> 6;
        int16_t max = (staticParams.servos[axis].maxValue * SERVO_NORMAL_LIMIT) >> 6;
 
        if (value < min) value = min;
        else if (value > max) value = max;
 
        if (value < -SERVO_ABS_LIMIT) value = -SERVO_ABS_LIMIT;
        else if (value > SERVO_ABS_LIMIT) value = SERVO_ABS_LIMIT;
 
        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.
  }
}
 

Rev 2135	Rev 2142
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 ((int16_t)(F_CPU/32000*1.5f + 0.5f))	12	#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/32000*1.5f + 0.5f))
13	#define STABILIZATION_LOG_DIVIDER 6	13	#define SERVO_NORMAL_LIMIT ((int16_t)(F_CPU/32000*0.5f + 0.5f))
14	#define SERVOLIMIT ((int16_t)(F_CPU/32000*0.8f + 0.5f))	14	#define SERVO_ABS_LIMIT ((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 ((int16_t)(F_CPU/8000.0f * 1.5f + 0.5f))	19	#define NEUTRAL_PULSELENGTH ((int16_t)(F_CPU/8000.0f * 1.5f + 0.5f))
20	#define STABILIZATION_LOG_DIVIDER 4	20	#define SERVO_NORMAL_LIMIT ((int16_t)(F_CPU/8000.0f * 0.5f + 0.5f))
21	#define SERVOLIMIT ((int16_t)(F_CPU/8000.0f * 0.8f + 0.5f))	21	#define SERVO_ABS_LIMIT ((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 FRAMELENGTH ((uint16_t)(NEUTRAL_PULSELENGTH + SERVOLIMIT) * (uint16_t)staticParams.servoCount + 128)	-
27	#define MIN_PULSELENGTH (NEUTRAL_PULSELENGTH - SERVOLIMIT)	-
28	#define MAX_PULSELENGTH (NEUTRAL_PULSELENGTH + SERVOLIMIT)	-
29		26	#define FRAMELENGTH ((uint16_t)(NEUTRAL_PULSELENGTH + SERVO_ABS_LIMIT) * (uint16_t)staticParams.servoCount + 128)
-		27
30	volatile uint8_t recalculateServoTimes = 0;	28	volatile uint16_t servoValues[MAX_SERVOS];
31	volatile uint16_t servoValues[MAX_SERVOS];	29	//volatile uint8_t recalculateServoTimes = 0;
32	volatile uint16_t previousManualValues[2];	30	//volatile uint16_t previousManualValues[2];
33		31
34	#define HEF4017R_ON PORTC \|= (1<<PORTC6)	32	#define HEF4017R_ON PORTC \|= (1<<PORTC6)
35	#define HEF4017R_OFF PORTC &= ~(1<<PORTC6)	33	#define HEF4017R_OFF PORTC &= ~(1<<PORTC6)
36		34
37	/*****************************************************	35	/*****************************************************
38	* Initialize Timer 2	36	* Initialize Timer 2
39	*****************************************************/	37	*****************************************************/
40	void timer2_init(void) {	38	void timer2_init(void) {
41	uint8_t sreg = SREG;	39	uint8_t sreg = SREG;
42		40
43	// disable all interrupts before reconfiguration	41	// disable all interrupts before reconfiguration
44	cli();	42	cli();
45		43
46	// set PD7 as output of the PWM for pitch servo	44	// set PD7 as output of the PWM for pitch servo
47	DDRD \|= (1 << DDD7);	45	DDRD \|= (1 << DDD7);
48	PORTD &= ~(1 << PORTD7); // set PD7 to low	46	PORTD &= ~(1 << PORTD7); // set PD7 to low
49		47
50	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)	48	DDRC \|= (1 << DDC6); // set PC6 as output (Reset for HEF4017)
51	HEF4017R_ON; // reset	49	HEF4017R_ON; // reset
52		50
53	// Timer/Counter 2 Control Register A	51	// Timer/Counter 2 Control Register A
54	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)	52	// Timer Mode is CTC (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 0)
55	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)	53	// PD7: Output OCR2 match, (Bits: COM2A1 = 1, COM2A0 = 0)
56	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)	54	// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0)
57	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));	55	TCCR2A &= ~((1 << COM2A0) \| (1 << COM2B1) \| (1 << COM2B0) \| (1 << WGM20) \| (1 << WGM22));
58	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);	56	TCCR2A \|= (1 << COM2A1) \| (1 << WGM21);
59		57
60	// Timer/Counter 2 Control Register B	58	// Timer/Counter 2 Control Register B
61		59
62	// Set clock divider for timer 2 to 20MHz / 8 = 2.5 MHz	60	// 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	61	// 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	62	// hence the timer overflow interrupt frequency is 625 kHz / 256 = 9.765 kHz or 0.1024ms
65		63
66	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));	64	TCCR2B &= ~((1 << FOC2A) \| (1 << FOC2B) \| (1 << CS20) \| (1 << CS21) \| (1 << CS22));
67	TCCR2B \|= CS2;	65	TCCR2B \|= CS2;
68		66
69	// Initialize the Timer/Counter 2 Register	67	// Initialize the Timer/Counter 2 Register
70	TCNT2 = 0;	68	TCNT2 = 0;
71		69
72	// Initialize the Output Compare Register A used for signal generation on port PD7.	70	// Initialize the Output Compare Register A used for signal generation on port PD7.
73	OCR2A = 255;	71	OCR2A = 255;
74		72
75	// Timer/Counter 2 Interrupt Mask Register	73	// Timer/Counter 2 Interrupt Mask Register
76	// Enable timer output compare match A Interrupt only	74	// Enable timer output compare match A Interrupt only
77	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));	75	TIMSK2 &= ~((1 << OCIE2B) \| (1 << TOIE2));
78	TIMSK2 \|= (1 << OCIE2A);	76	TIMSK2 \|= (1 << OCIE2A);
79		77
80	for (uint8_t axis=0; axis<2; axis++)	78	for (uint8_t i=0; i<MAX_SERVOS; i++)
81	previousManualValues[axis] = dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR;	79	servoValues[i] = NEUTRAL_PULSELENGTH;
82		80
83	SREG = sreg;	81	SREG = sreg;
84	}	82	}
85		83
86	/*****************************************************	84	/*****************************************************
87	* Control (camera gimbal etc.) servos	85	* Control (camera gimbal etc.) servos
88	*****************************************************/	86	*****************************************************/
-		87	/*
89	int16_t calculateStabilizedServoAxis(uint8_t axis) {	88	int16_t calculateStabilizedServoAxis(uint8_t axis) {
90	int32_t value = attitude[axis] >> STABILIZATION_LOG_DIVIDER; // between -500000 to 500000 extreme limits. Just about	89	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.	90	// 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.	91	// That is a divisor of about 1<<14. Same conclusion as H&I.
93	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;	92	value *= staticParams.gimbalServoConfigurations[axis].stabilizationFactor;
94	value = value >> 8;	93	value = value >> 8;
95	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)	94	if (staticParams.gimbalServoConfigurations[axis].flags & SERVO_STABILIZATION_REVERSE)
96	return -value;	95	return -value;
97	return value;	96	return value;
98	}	97	}
99		98
100	// With constant-speed limitation.	99	// With constant-speed limitation.
101	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {	100	uint16_t calculateManualServoAxis(uint8_t axis, uint16_t manualValue) {
102	int16_t diff = manualValue - previousManualValues[axis];	101	int16_t diff = manualValue - previousManualValues[axis];
103	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;	102	uint8_t maxSpeed = staticParams.gimbalServoMaxManualSpeed;
104	if (diff > maxSpeed) diff = maxSpeed;	103	if (diff > maxSpeed) diff = maxSpeed;
105	else if (diff < -maxSpeed) diff = -maxSpeed;	104	else if (diff < -maxSpeed) diff = -maxSpeed;
106	manualValue = previousManualValues[axis] + diff;	105	manualValue = previousManualValues[axis] + diff;
107	previousManualValues[axis] = manualValue;	106	previousManualValues[axis] = manualValue;
108	return manualValue;	107	return manualValue;
109	}	108	}
-		109	*/
-		110
110		111	/*
111	// add stabilization and manual, apply soft position limits.	112	// add stabilization and manual, apply soft position limits.
112	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)	113	// All in a [0..255*SCALE_FACTOR] space (despite signed types used internally)
113	int16_t featuredServoValue(uint8_t axis) {	114	int16_t featuredServoValue(uint8_t axis) {
114	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);	115	int16_t value = calculateManualServoAxis(axis, dynamicParams.gimbalServoManualControl[axis] * SCALE_FACTOR);
115	value += calculateStabilizedServoAxis(axis);	116	value += calculateStabilizedServoAxis(axis);
116	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;	117	int16_t limit = staticParams.gimbalServoConfigurations[axis].minValue * SCALE_FACTOR;
117	if (value < limit) value = limit;	118	if (value < limit) value = limit;
118	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;	119	limit = staticParams.gimbalServoConfigurations[axis].maxValue * SCALE_FACTOR;
119	if (value > limit) value = limit;	120	if (value > limit) value = limit;
120	value -= (128 * SCALE_FACTOR);	121	value -= (128 * SCALE_FACTOR);
121	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	122	if (value < -SERVOLIMIT) value = -SERVOLIMIT;
122	else if (value > SERVOLIMIT) value = SERVOLIMIT;	123	else if (value > SERVOLIMIT) value = SERVOLIMIT;
123	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.	124	// Shift into the [NEUTRAL_PULSELENGTH-SERVOLIMIT..NEUTRAL_PULSELENGTH+SERVOLIMIT] space.
124	return value + NEUTRAL_PULSELENGTH;	125	return value + NEUTRAL_PULSELENGTH;
125	}	126	}
-		127	*/
126		128
127	void calculateControlServoValues(void) {	129	void calculateControlServoValues(void) {
128	int16_t value;	130	int16_t value;
129	//int16_t minLimit = staticParams.controlServoMinValue * SCALE_FACTOR;	-
130	//int16_t maxLimit = staticParams.controlServoMaxValue * SCALE_FACTOR;	-
131	for (uint8_t axis=0; axis<4; axis++) {	131	for (uint8_t axis=0; axis<4; axis++) {
132	value = controlServos[axis];	132	value = controlServos[axis];
-		133
-		134	// Apply configurable limits. These are signed: +-128 is twice the normal +- 0.5 ms limit and +- 64 is normal.
-		135	int16_t min = (staticParams.servos[axis].minValue * SERVO_NORMAL_LIMIT) >> 6;
-		136	int16_t max = (staticParams.servos[axis].maxValue * SERVO_NORMAL_LIMIT) >> 6;
-		137
-		138	if (value < min) value = min;
-		139	else if (value > max) value = max;
-		140
133	if (value < -SERVOLIMIT) value = -SERVOLIMIT;	141	if (value < -SERVO_ABS_LIMIT) value = -SERVO_ABS_LIMIT;
134	else if (value > SERVOLIMIT) value = SERVOLIMIT;	142	else if (value > SERVO_ABS_LIMIT) value = SERVO_ABS_LIMIT;
-		143
135	servoValues[axis] = value + NEUTRAL_PULSELENGTH;	144	servoValues[axis] = value + NEUTRAL_PULSELENGTH;
136	}	145	}
137	}	146	}
-		147
138		148	/*
139	void calculateFeaturedServoValues(void) {	149	void calculateFeaturedServoValues(void) {
140	int16_t value;	150	int16_t value;
141	uint8_t axis;	151	uint8_t axis;
142		152
143	// Save the computation cost of computing a new value before the old one is used.	153	// Save the computation cost of computing a new value before the old one is used.
144	if (!recalculateServoTimes) return;	154	if (!recalculateServoTimes) return;
145		155
146	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {	156	for (axis= MAX_CONTROL_SERVOS; axis<MAX_CONTROL_SERVOS+2; axis++) {
147	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);	157	value = featuredServoValue(axis-MAX_CONTROL_SERVOS);
148	servoValues[axis] = value;	158	servoValues[axis] = value;
149	}	159	}
150	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {	160	for (axis=MAX_CONTROL_SERVOS+2; axis<MAX_SERVOS; axis++) {
151	value = 128 * SCALE_FACTOR;	161	value = 128 * SCALE_FACTOR;
152	servoValues[axis] = value;	162	servoValues[axis] = value;
153	}	163	}
154		164
155	recalculateServoTimes = 0;	165	recalculateServoTimes = 0;
156	}	166	}
-		167	*/
157		168
158	ISR(TIMER2_COMPA_vect) {	169	ISR(TIMER2_COMPA_vect) {
159	static uint16_t remainingPulseTime;	170	static uint16_t remainingPulseTime;
160	static uint8_t servoIndex = 0;	171	static uint8_t servoIndex = 0;
161	static uint16_t sumOfPulseTimes = 0;	172	static uint16_t sumOfPulseTimes = 0;
162		173
163	if (!remainingPulseTime) {	174	if (!remainingPulseTime) {
164	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.	175	// Pulse is over, and the next pulse has already just started. Calculate length of next pulse.
165	if (servoIndex < staticParams.servoCount) {	176	if (servoIndex < staticParams.servoCount) {
166	// There are more signals to output.	177	// There are more signals to output.
167	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);	178	sumOfPulseTimes += (remainingPulseTime = servoValues[servoIndex]);
168	servoIndex++;	179	servoIndex++;
169	} else {	180	} else {
170	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.	181	// There are no more signals. Reset the counter and make this pulse cover the missing frame time.
171	remainingPulseTime = FRAMELENGTH - sumOfPulseTimes;	182	remainingPulseTime = FRAMELENGTH - sumOfPulseTimes;
172	sumOfPulseTimes = servoIndex = 0;	183	sumOfPulseTimes = servoIndex = 0;
173	recalculateServoTimes = 1;	184	//recalculateServoTimes = 1;
174	HEF4017R_ON;	185	HEF4017R_ON;
175	}	186	}
176	}	187	}
177		188
178	// Schedule the next OCR2A event. The counter is already reset at this time.	189	// Schedule the next OCR2A event. The counter is already reset at this time.
179	if (remainingPulseTime > 256+128) {	190	if (remainingPulseTime > 256+128) {
180	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,	191	// Set output to reset to zero at next OCR match. It does not really matter when the output is set low again,
181	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.	192	// as long as it happens once per pulse. This will, because all pulses are > 255+128 long.
182	OCR2A = 255;	193	OCR2A = 255;
183	TCCR2A &= ~(1<<COM2A0);	194	TCCR2A &= ~(1<<COM2A0);
184	remainingPulseTime-=256;	195	remainingPulseTime-=256;
185	} else if (remainingPulseTime > 256) {	196	} else if (remainingPulseTime > 256) {
186	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard	197	// Remaining pulse lengths in the range [256..256+128] might cause trouble if handled the standard
187	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt	198	// way, which is in chunks of 256. The remainder would be very small, possibly causing an interrupt on interrupt
188	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.	199	// condition. Instead we now make a chunk of 128. The remaining chunk will then be in [128..255] which is OK.
189	remainingPulseTime-=128;	200	remainingPulseTime-=128;
190	OCR2A=127;	201	OCR2A=127;
191	} else {	202	} else {
192	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low	203	// Set output to high at next OCR match. This is when the 4017 counter will advance by one. Also set reset low
193	TCCR2A \|= (1<<COM2A0);	204	TCCR2A \|= (1<<COM2A0);
194	OCR2A = remainingPulseTime-1;	205	OCR2A = remainingPulseTime-1;
195	remainingPulseTime=0;	206	remainingPulseTime=0;
196	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.	207	HEF4017R_OFF; // implement servo-disable here, by only removing the reset signal if ServoEnabled!=0.
197	}	208	}
198	}	209	}
199		210

Subversion Repositories FlightCtrl

(root)/branches/dongfang_FC_fixedwing/timer2.c @ 2088 - Rev 2135 → 2142