WebSVN - FlightCtrl - Diff - Rev 1227 and 1235 - /branches/V0.74d Code Redesign killagreg/rc.c


// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) 04.2007 Holger Buss
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),
// + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist.
// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt
// + bzgl. der Nutzungsbedingungen aufzunehmen.
// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
// + Verkauf von Luftbildaufnahmen, usw.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,
// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts
// + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"
// + eindeutig als Ursprung verlinkt werden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion
// + Benutzung auf eigene Gefahr
// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur
// + mit unserer Zustimmung zulässig
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
// + this list of conditions and the following disclaimer.
// +   * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived
// +     from this software without specific prior written permission.
// +   * The use of this project (hardware, software, binary files, sources and documentation) is only permittet
// +     for non-commercial use (directly or indirectly)
// +     Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted
// +     with our written permission
// +   * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be
// +     clearly linked as origin
// +   * porting to systems other than hardware from www.mikrokopter.de is not allowed
// +  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// +  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// +  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// +  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// +  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// +  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// +  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// +  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// +  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// +  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// +  POSSIBILITY OF SUCH DAMAGE.
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <stdlib.h>
#include <avr/io.h>
#include <avr/interrupt.h>
 
#include "rc.h"
#include "main.h"
 
volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame
volatile int16_t PPM_diff[15];
volatile uint8_t NewPpmData = 1;
volatile int16_t RC_Quality = 0;
 
 
 
/***************************************************************/
/*  16bit timer 1 is used to decode the PPM-Signal            */
/***************************************************************/
void RC_Init (void)
{
        uint8_t sreg = SREG;
 
        // disable all interrupts before reconfiguration
        cli();
 
        // PPM-signal is connected to the Input Capture Pin (PD6) of timer 1
        DDRD &= ~(1<<DDD6);
        PORTD |= (1<<PORTD6);
 
        // Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5)
        // set as output
        DDRD |= (1<<DDD5)|(1<<DDD4);
        // low level
        PORTD &= ~((1<<PORTD5)|(1<<PORTD4));
 
        // PD3 can't be used if 2nd UART is activated
        // because TXD1 is at that port
        if(CPUType != ATMEGA644P)
        {
                DDRD |= (1<<PORTD3);
                PORTD &= ~(1<<PORTD3);
        }
 
        // Timer/Counter1 Control Register A, B, C
 
        // Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0)
        // Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0)
        // Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1)
        // Enable input capture noise cancler (bit: ICNC1=1)
        // Trigger on positive edge of the input capture pin (bit: ICES1=1),
        // Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs
    // The longest period is 0xFFFF / 312.5 kHz = 0.209712 s.
        TCCR1A &= ~((1<<COM1A1)|(1<<COM1A0)|(1<<COM1B1)|(1<<COM1B0)|(1<<WGM11)|(1<<WGM10));
        TCCR1B &= ~((1<<WGM13)|(1<<WGM12)|(1<<CS12));
        TCCR1B |= (1<<CS11)|(1<<CS10)|(1<<ICES1)|(1<<ICNC1);
        TCCR1C &= ~((1<<FOC1A)|(1<<FOC1B));
 
        // Timer/Counter1 Interrupt Mask Register
 
        // Enable Input Capture Interrupt (bit: ICIE1=1)
        // Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0)
        // Enable Overflow Interrupt (bit: TOIE1=0)
        TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)|(1<<TOIE1));
    TIMSK1 |= (1<<ICIE1);
 
    RC_Quality = 0;
 
    SREG = sreg;
}
 
 
/********************************************************************/
/*         Every time a positive edge is detected at PD6            */
/********************************************************************/
/*                               t-Frame
       <----------------------------------------------------------------------->
         ____   ______   _____   ________                ______    sync gap      ____
        |    | |      | |     | |        |              |      |                |
        |    | |      | |     | |        |              |      |                |
     ___|    |_|      |_|     |_|        |_.............|      |________________|
        <-----><-------><------><-------->              <------>                <---
          t0       t1      t2       t4                     tn                     t0
 
The PPM-Frame length is 22.5 ms.
Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse.
The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms.
The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms.
The minimum duration of all channels at minimum value is  8 * 1 ms = 8 ms.
The maximum duration of all channels at maximum value is  8 * 2 ms = 16 ms.
The remaining time of (22.5 - 8 ms) ms = 14.5 ms  to (22.5 - 16 ms) ms = 6.5 ms is
the syncronization gap.
*/
ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms
{
    int16_t signal = 0, tmp;
        static int16_t index;
        static uint16_t oldICR1 = 0;
 
        // 16bit Input Capture Register ICR1 contains the timer value TCNT1
        // at the time the edge was detected
 
        // calculate the time delay to the previous event time which is stored in oldICR1
        // calculatiing the difference of the two uint16_t and converting the result to an int16_t
        // implicit handles a timer overflow 65535 -> 0 the right way.
        signal = (uint16_t) ICR1 - oldICR1;
        oldICR1 = ICR1;
 
    //sync gap? (3.52 ms < signal < 25.6 ms)
        if((signal > 1100) && (signal < 8000))
        {
                // if a sync gap happens and there where at least 4 channels decoded before
                // then the NewPpmData flag is reset indicating valid data in the PPM_in[] array.
                if(index >= 4)
                {
                        NewPpmData = 0;  // Null means NewData for the first 4 channels
                }
                // synchronize channel index
                index = 1;
        }
        else // within the PPM frame
    {
        if(index < 14) // PPM24 supports 12 channels
        {
                        // check for valid signal length (0.8 ms < signal < 2.1984 ms)
                        // signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625
            if((signal > 250) && (signal < 687))
            {
                                // shift signal to zero symmetric range  -154 to 159
                signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms)
                // check for stable signal
                if(abs(signal - PPM_in[index]) < 6)
                {
                                        if(RC_Quality < 200) RC_Quality +=10;
                                        else RC_Quality = 200;
                                }
                                // calculate exponential history for signal
                tmp = (3 * (PPM_in[index]) + signal) / 4;
                if(tmp > signal+1) tmp--; else
                if(tmp < signal-1) tmp++;
                // calculate signal difference on good signal level
                if(RC_Quality >= 195)  PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction
                else PPM_diff[index] = 0;
                PPM_in[index] = tmp; // update channel value
            }
            index++; // next channel
            // demux sum signal for channels 5 to 7 to J3, J4, J5
                if(index == 5) J3HIGH; else J3LOW;
                if(index == 6) J4HIGH; else J4LOW;
                if(CPUType != ATMEGA644P) // not used as TXD1
                {
                                if(index == 7) J5HIGH; else J5LOW;
                }
        }
        }
}
 
 
 
 
 
 

Subversion Repositories FlightCtrl

(root)/branches/V0.74d Code Redesign killagreg/rc.c @ 2361 - Rev 1227 → 1235

Rev 1227		Rev 1235
1	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	1	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2	// + Copyright (c) 04.2007 Holger Buss	2	// + Copyright (c) 04.2007 Holger Buss
3	// + Nur für den privaten Gebrauch	3	// + Nur für den privaten Gebrauch
4	// + www.MikroKopter.com	4	// + www.MikroKopter.com
5	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	5	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
6	// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),	6	// + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation),
7	// + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist.	7	// + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist.
8	// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt	8	// + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt
9	// + bzgl. der Nutzungsbedingungen aufzunehmen.	9	// + bzgl. der Nutzungsbedingungen aufzunehmen.
10	// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,	10	// + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen,
11	// + Verkauf von Luftbildaufnahmen, usw.	11	// + Verkauf von Luftbildaufnahmen, usw.
12	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	12	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
13	// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,	13	// + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht,
14	// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen	14	// + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen
15	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	15	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
16	// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts	16	// + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts
17	// + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"	17	// + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de"
18	// + eindeutig als Ursprung verlinkt werden	18	// + eindeutig als Ursprung verlinkt werden
19	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	19	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20	// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion	20	// + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion
21	// + Benutzung auf eigene Gefahr	21	// + Benutzung auf eigene Gefahr
22	// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden	22	// + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden
23	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	23	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
24	// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur	24	// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur
25	// + mit unserer Zustimmung zulässig	25	// + mit unserer Zustimmung zulässig
26	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	26	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
27	// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen	27	// + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen
28	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	28	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
29	// + Redistributions of source code (with or without modifications) must retain the above copyright notice,	29	// + Redistributions of source code (with or without modifications) must retain the above copyright notice,
30	// + this list of conditions and the following disclaimer.	30	// + this list of conditions and the following disclaimer.
31	// + * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived	31	// + * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived
32	// + from this software without specific prior written permission.	32	// + from this software without specific prior written permission.
33	// + * The use of this project (hardware, software, binary files, sources and documentation) is only permittet	33	// + * The use of this project (hardware, software, binary files, sources and documentation) is only permittet
34	// + for non-commercial use (directly or indirectly)	34	// + for non-commercial use (directly or indirectly)
35	// + Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted	35	// + Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted
36	// + with our written permission	36	// + with our written permission
37	// + * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be	37	// + * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be
38	// + clearly linked as origin	38	// + clearly linked as origin
39	// + * porting to systems other than hardware from www.mikrokopter.de is not allowed	39	// + * porting to systems other than hardware from www.mikrokopter.de is not allowed
40	// + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"	40	// + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
41	// + AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE	41	// + AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42	// + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE	42	// + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43	// + ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE	43	// + ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
44	// + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR	44	// + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
45	// + CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF	45	// + CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
46	// + SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS	46	// + SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
47	// + INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// + CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)	47	// + INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// + CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
48	// + ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE	48	// + ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
49	// + POSSIBILITY OF SUCH DAMAGE.	49	// + POSSIBILITY OF SUCH DAMAGE.
50	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++	50	// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
51	#include <stdlib.h>	51	#include <stdlib.h>
52	#include <avr/io.h>	52	#include <avr/io.h>
53	#include <avr/interrupt.h>	53	#include <avr/interrupt.h>
54		54
55	#include "rc.h"	55	#include "rc.h"
56	#include "main.h"	56	#include "main.h"
57		57
58	volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame	58	volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame
59	volatile int16_t PPM_diff[15];	59	volatile int16_t PPM_diff[15];
60	volatile uint8_t NewPpmData = 1;	60	volatile uint8_t NewPpmData = 1;
61	volatile int16_t RC_Quality = 0;	61	volatile int16_t RC_Quality = 0;
62		62
63		63
64		64
65	/***************************************************************/	65	/***************************************************************/
66	/* 16bit timer 1 is used to decode the PPM-Signal */	66	/* 16bit timer 1 is used to decode the PPM-Signal */
67	/***************************************************************/	67	/***************************************************************/
68	void RC_Init (void)	68	void RC_Init (void)
69	{	69	{
70	uint8_t sreg = SREG;	70	uint8_t sreg = SREG;
71		71
72	// disable all interrupts before reconfiguration	72	// disable all interrupts before reconfiguration
73	cli();	73	cli();
74		74
75	// PPM-signal is connected to the Input Capture Pin (PD6) of timer 1	75	// PPM-signal is connected to the Input Capture Pin (PD6) of timer 1
76	DDRD &= ~(1<<DDD6);	76	DDRD &= ~(1<<DDD6);
77	PORTD \|= (1<<PORTD6);	77	PORTD \|= (1<<PORTD6);
78		78
79	// Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5)	79	// Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5)
80	// set as output	80	// set as output
81	DDRD \|= (1<<DDD5)\|(1<<DDD4);	81	DDRD \|= (1<<DDD5)\|(1<<DDD4);
82	// low level	82	// low level
83	PORTD &= ~((1<<PORTD5)\|(1<<PORTD4));	83	PORTD &= ~((1<<PORTD5)\|(1<<PORTD4));
84		84
85	// PD3 can't be used if 2nd UART is activated	85	// PD3 can't be used if 2nd UART is activated
86	// because TXD1 is at that port	86	// because TXD1 is at that port
87	if(CPUType != ATMEGA644P)	87	if(CPUType != ATMEGA644P)
88	{	88	{
89	DDRD \|= (1<<PORTD3);	89	DDRD \|= (1<<PORTD3);
90	PORTD &= ~(1<<PORTD3);	90	PORTD &= ~(1<<PORTD3);
91	}	91	}
92		92
93	// Timer/Counter1 Control Register A, B, C	93	// Timer/Counter1 Control Register A, B, C
94		94
95	// Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0)	95	// Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0)
96	// Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0)	96	// Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0)
97	// Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1)	97	// Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1)
98	// Enable input capture noise cancler (bit: ICNC1=1)	98	// Enable input capture noise cancler (bit: ICNC1=1)
99	// Trigger on positive edge of the input capture pin (bit: ICES1=1),	99	// Trigger on positive edge of the input capture pin (bit: ICES1=1),
100	// Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs	100	// Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs
101	// The longest period is 0xFFFF / 312.5 kHz = 0.209712 s.	101	// The longest period is 0xFFFF / 312.5 kHz = 0.209712 s.
102	TCCR1A &= ~((1<<COM1A1)\|(1<<COM1A0)\|(1<<COM1B1)\|(1<<COM1B0)\|(1<<WGM11)\|(1<<WGM10));	102	TCCR1A &= ~((1<<COM1A1)\|(1<<COM1A0)\|(1<<COM1B1)\|(1<<COM1B0)\|(1<<WGM11)\|(1<<WGM10));
103	TCCR1B &= ~((1<<WGM13)\|(1<<WGM12)\|(1<<CS12));	103	TCCR1B &= ~((1<<WGM13)\|(1<<WGM12)\|(1<<CS12));
104	TCCR1B \|= (1<<CS11)\|(1<<CS10)\|(1<<ICES1)\|(1<<ICNC1);	104	TCCR1B \|= (1<<CS11)\|(1<<CS10)\|(1<<ICES1)\|(1<<ICNC1);
105	TCCR1C &= ~((1<<FOC1A)\|(1<<FOC1B));	105	TCCR1C &= ~((1<<FOC1A)\|(1<<FOC1B));
106		106
107	// Timer/Counter1 Interrupt Mask Register	107	// Timer/Counter1 Interrupt Mask Register
108		108
109	// Enable Input Capture Interrupt (bit: ICIE1=1)	109	// Enable Input Capture Interrupt (bit: ICIE1=1)
110	// Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0)	110	// Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0)
111	// Enable Overflow Interrupt (bit: TOIE1=0)	111	// Enable Overflow Interrupt (bit: TOIE1=0)
112	TIMSK1 &= ~((1<<OCIE1B)\|(1<<OCIE1A)\|(1<<TOIE1));	112	TIMSK1 &= ~((1<<OCIE1B)\|(1<<OCIE1A)\|(1<<TOIE1));
113	TIMSK1 \|= (1<<ICIE1);	113	TIMSK1 \|= (1<<ICIE1);
114		114
115	RC_Quality = 0;	115	RC_Quality = 0;
116		116
117	SREG = sreg;	117	SREG = sreg;
118	}	118	}
119		119
120		120
121	/********************************************************************/	121	/********************************************************************/
122	/* Every time a positive edge is detected at PD6 */	122	/* Every time a positive edge is detected at PD6 */
123	/********************************************************************/	123	/********************************************************************/
124	/* t-Frame	124	/* t-Frame
125	<----------------------------------------------------------------------->	125	<----------------------------------------------------------------------->
126	____ ______ _____ ________ ______ sync gap ____	126	____ ______ _____ ________ ______ sync gap ____
127	\| \| \| \| \| \| \| \| \| \| \|	127	\| \| \| \| \| \| \| \| \| \| \|
128	\| \| \| \| \| \| \| \| \| \| \|	128	\| \| \| \| \| \| \| \| \| \| \|
129	___\| \|_\| \|_\| \|_\| \|_.............\| \|________________\|	129	___\| \|_\| \|_\| \|_\| \|_.............\| \|________________\|
130	<-----><-------><------><--------> <------> <---	130	<-----><-------><------><--------> <------> <---
131	t0 t1 t2 t4 tn t0	131	t0 t1 t2 t4 tn t0
132		132
133	The PPM-Frame length is 22.5 ms.	133	The PPM-Frame length is 22.5 ms.
134	Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse.	134	Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse.
135	The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms.	135	The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms.
136	The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms.	136	The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms.
137	The minimum duration of all channels at minimum value is 8 * 1 ms = 8 ms.	137	The minimum duration of all channels at minimum value is 8 * 1 ms = 8 ms.
138	The maximum duration of all channels at maximum value is 8 * 2 ms = 16 ms.	138	The maximum duration of all channels at maximum value is 8 * 2 ms = 16 ms.
139	The remaining time of (22.5 - 8 ms) ms = 14.5 ms to (22.5 - 16 ms) ms = 6.5 ms is	139	The remaining time of (22.5 - 8 ms) ms = 14.5 ms to (22.5 - 16 ms) ms = 6.5 ms is
140	the syncronization gap.	140	the syncronization gap.
141	*/	141	*/
142	ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms	142	ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms
143	{	143	{
144	int16_t signal = 0, tmp;	144	int16_t signal = 0, tmp;
145	static int16_t index;	145	static int16_t index;
146	static uint16_t oldICR1 = 0;	146	static uint16_t oldICR1 = 0;
147		147
148	// 16bit Input Capture Register ICR1 contains the timer value TCNT1	148	// 16bit Input Capture Register ICR1 contains the timer value TCNT1
149	// at the time the edge was detected	149	// at the time the edge was detected
150		150
151	// calculate the time delay to the previous event time which is stored in oldICR1	151	// calculate the time delay to the previous event time which is stored in oldICR1
152	// calculatiing the difference of the two uint16_t and converting the result to an int16_t	152	// calculatiing the difference of the two uint16_t and converting the result to an int16_t
153	// implicit handles a timer overflow 65535 -> 0 the right way.	153	// implicit handles a timer overflow 65535 -> 0 the right way.
154	signal = (uint16_t) ICR1 - oldICR1;	154	signal = (uint16_t) ICR1 - oldICR1;
155	oldICR1 = ICR1;	155	oldICR1 = ICR1;
156		156
157	//sync gap? (3.52 ms < signal < 25.6 ms)	157	//sync gap? (3.52 ms < signal < 25.6 ms)
158	if((signal > 1100) && (signal < 8000))	158	if((signal > 1100) && (signal < 8000))
159	{	159	{
160	// if a sync gap happens and there where at least 4 channels decoded before	160	// if a sync gap happens and there where at least 4 channels decoded before
161	// then the NewPpmData flag is reset indicating valid data in the PPM_in[] array.	161	// then the NewPpmData flag is reset indicating valid data in the PPM_in[] array.
162	if(index >= 4)	162	if(index >= 4)
163	{	163	{
164	NewPpmData = 0; // Null means NewData for the first 4 channels	164	NewPpmData = 0; // Null means NewData for the first 4 channels
165	}	165	}
166	// synchronize channel index	166	// synchronize channel index
167	index = 1;	167	index = 1;
168	}	168	}
169	else // within the PPM frame	169	else // within the PPM frame
170	{	170	{
171	if(index < 14) // PPM24 supports 12 channels	171	if(index < 14) // PPM24 supports 12 channels
172	{	172	{
173	// check for valid signal length (0.8 ms < signal < 2.1984 ms)	173	// check for valid signal length (0.8 ms < signal < 2.1984 ms)
174	// signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625	174	// signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625
175	if((signal > 250) && (signal < 687))	175	if((signal > 250) && (signal < 687))
176	{	176	{
177	// shift signal to zero symmetric range -154 to 159	177	// shift signal to zero symmetric range -154 to 159
178	signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms)	178	signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms)
179	// check for stable signal	179	// check for stable signal
180	if(abs(signal - PPM_in[index]) < 6)	180	if(abs(signal - PPM_in[index]) < 6)
181	{	181	{
182	if(RC_Quality < 200) RC_Quality +=10;	182	if(RC_Quality < 200) RC_Quality +=10;
183	else RC_Quality = 200;	183	else RC_Quality = 200;
184	}	184	}
185	// calculate exponential history for signal	185	// calculate exponential history for signal
186	tmp = (3 * (PPM_in[index]) + signal) / 4;	186	tmp = (3 * (PPM_in[index]) + signal) / 4;
187	if(tmp > signal+1) tmp--; else	187	if(tmp > signal+1) tmp--; else
188	if(tmp < signal-1) tmp++;	188	if(tmp < signal-1) tmp++;
189	// calculate signal difference on good signal level	189	// calculate signal difference on good signal level
190	if(RC_Quality >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction	190	if(RC_Quality >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction
191	else PPM_diff[index] = 0;	191	else PPM_diff[index] = 0;
192	PPM_in[index] = tmp; // update channel value	192	PPM_in[index] = tmp; // update channel value
193	}	193	}
194	index++; // next channel	194	index++; // next channel
195	// demux sum signal for channels 5 to 7 to J3, J4, J5	195	// demux sum signal for channels 5 to 7 to J3, J4, J5
196	if(index == 5) J3HIGH; else J3LOW;	196	if(index == 5) J3HIGH; else J3LOW;
197	if(index == 6) J4HIGH; else J3LOW;	197	if(index == 6) J4HIGH; else J4LOW;
198	if(CPUType != ATMEGA644P) // not used as TXD1	198	if(CPUType != ATMEGA644P) // not used as TXD1
199	{	199	{
200	if(index == 7) J5HIGH; else J5LOW;	200	if(index == 7) J5HIGH; else J5LOW;
201	}	201	}
202	}	202	}
203	}	203	}
204	}	204	}
205		205
206		206
207		207
208		208
209		209
210		210