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| /*------------------------------------------------------------------------------ |
| ** Ident : main.c ** |
| ** Project : MX16s 8->10 ppm channel expander ** |
| ** Author : lakeroe ** |
| ** Description : main module ** |
| ** Copyright (c) : 12.2011 lakeroe ** |
| ** Original code and idea : Jacques Wanders ** |
| ** http://forum.mikrokopter.de/topic-4405.html ** |
| ** http://forum.mikrokopter.de/topic-4556.html ** |
| **----------------------------------------------------------------------------** |
| ** Release : v1.0 initial release ** |
| ** Date : 25-12-2011 ** |
| **----------------------------------------------------------------------------** |
| ** The use of this project (hardware, software, binary files, sources and ** |
| ** documentation) is only permittet for non-commercial use ** |
| ** (directly or indirectly) ** |
| ** 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 <avr/io.h> |
| #include <avr/interrupt.h> |
| #include "main.h" |
| |
| enum |
| { |
| stPPM_SYNC, |
| stPPM_SYNC_WAIT, |
| stPPM_CHANNEL_START, |
| stPPM_CHANNEL_DATA, |
| stPPM_CHANNEL_9_DATA, |
| stPPM_CHANNEL_10_START, |
| stPPM_CHANNEL_10_DATA, |
| stPPM_FINISH_PULSE, |
| stPPM_FRAME_END |
| }; |
| |
| unsigned char channel_number = 0; |
| unsigned char ppm_state = stPPM_SYNC; |
| |
| // timer1_capture_interrupt (void) |
| // Synchronise PPM frame and copy input events to PPM_OUT, start mixing Ch9,10 data when detect start pulse of Ch9 |
| ISR (TIM1_CAPT_vect) |
| { |
| cli (); // disable interrupts |
| unsigned int data; |
| |
| switch (ppm_state) |
| { |
| case stPPM_SYNC: // detect rising edge pulse |
| data = ICR1; // get timer value after input capture |
| SET_COUNTER_TO_ZERO; |
| FALLING_EDGE_TRIGGER; |
| if(data >= MIN_SYNC_TIME && data <= MAX_SYNC_TIME) // valid sync trigger |
| { |
| SET_PPM_OUT_HIGH; |
| ppm_state = stPPM_CHANNEL_DATA; // next state: get data |
| channel_number = 0; |
| } |
| else // trigger but not a valid sync time |
| { |
| SET_PPM_OUT_LOW; |
| ppm_state = stPPM_SYNC_WAIT; // next state: wait for next sync event |
| } |
| break; |
| |
| case stPPM_SYNC_WAIT: // detect falling edge pulse |
| SET_PPM_OUT_LOW; // not nessecery, output should already be low |
| SET_COUNTER_TO_ZERO; |
| SET_CAPTURE_COUNTER_TO_ZERO; |
| RISING_EDGE_TRIGGER; |
| ppm_state = stPPM_SYNC; // next state: try again for new sync |
| break; |
| |
| case stPPM_CHANNEL_START: // detect rising edge pulse |
| SET_COUNTER_TO_ZERO; |
| SET_PPM_OUT_HIGH; |
| FALLING_EDGE_TRIGGER; |
| channel_number++; // prepare for next MX16s channel clock |
| if(channel_number>7) // all eight channels read |
| { |
| SET_COUNTER_TO_ZERO; |
| SET_PPM_OUT_HIGH; |
| SET_TIMER_TO_COMPA_CTC; |
| DISABLE_INPUT_CAPTURE; |
| ENABLE_OUTPUT_COMPARE; |
| OCR1A = START_PULSE; // startpulse length 0.4ms |
| TRIGGER_INPUT_COMPARE_INTERRUPT; |
| ppm_state = stPPM_CHANNEL_9_DATA; // 9th. channel but now self created |
| channel_number = 0; |
| } |
| else |
| ppm_state = stPPM_CHANNEL_DATA; |
| break; |
| |
| case stPPM_CHANNEL_DATA: // detect falling edge pulse |
| SET_COUNTER_TO_ZERO; |
| SET_PPM_OUT_LOW; |
| RISING_EDGE_TRIGGER; |
| ppm_state = stPPM_CHANNEL_START; // wait for next channel rising edge pulse |
| break; |
| |
| default: |
| SET_PPM_OUT_LOW; // not nessecery, output should already be low |
| SET_COUNTER_TO_ZERO; |
| SET_CAPTURE_COUNTER_TO_ZERO; |
| RISING_EDGE_TRIGGER; |
| ppm_state = stPPM_SYNC; // next state: try again for new sync |
| break; |
| } |
| sei (); |
| } |
| |
| // timer1_compare_interrupt (void) |
| // Mixing channel 9,10 data into ppm out, start input capture for frame synchronisation |
| ISR (TIM1_COMPA_vect) |
| { |
| cli (); |
| switch (ppm_state) |
| { |
| case stPPM_CHANNEL_9_DATA: |
| SET_PPM_OUT_LOW; |
| SET_COUNTER_TO_ZERO; |
| if (PINA & (1 << CHANNEL_9)) // Channel 9 on/off |
| OCR1A = PPM_PULSE_MAX - START_PULSE; |
| else |
| OCR1A = PPM_PULSE_MIN - START_PULSE; |
| // set OCR1A between [PPM_PULSE_MIN-START_PULSE] and [PPM_PULSE_MAX-START_PULSE] for transmitting analog value |
| ppm_state = stPPM_CHANNEL_10_START; // next State |
| break; |
| |
| case stPPM_CHANNEL_10_START: |
| SET_PPM_OUT_HIGH; |
| SET_COUNTER_TO_ZERO; |
| OCR1A = START_PULSE; // startpulse length 0.4ms |
| ppm_state = stPPM_CHANNEL_10_DATA; // next State |
| break; |
| |
| case stPPM_CHANNEL_10_DATA: |
| SET_PPM_OUT_LOW; |
| SET_COUNTER_TO_ZERO; |
| if (PINA & (1 << CHANNEL_10)) // Channel 10 on/off |
| OCR1A = PPM_PULSE_MAX - START_PULSE; |
| else |
| OCR1A = PPM_PULSE_MIN - START_PULSE; |
| // set OCR1A between [PPM_PULSE_MIN-START_PULSE] and [PPM_PULSE_MAX-START_PULSE] for transmitting analog value |
| ppm_state = stPPM_FINISH_PULSE; // next State |
| break; |
| |
| case stPPM_FINISH_PULSE: // create last pulse |
| SET_PPM_OUT_HIGH; |
| SET_COUNTER_TO_ZERO; |
| OCR1A = START_PULSE; // startpulse length 0.4ms |
| ppm_state = stPPM_FRAME_END; // next State |
| break; |
| |
| case stPPM_FRAME_END: |
| default: |
| SET_PPM_OUT_LOW; |
| RISING_EDGE_TRIGGER; |
| DISABLE_OUTPUT_COMPARE; |
| ENABLE_INPUT_CAPTURE; |
| SET_TIMER_TO_COMPA_CTC; |
| SET_COUNTER_TO_ZERO; |
| SET_COMPARE_COUNTER_TO_ZERO; |
| SET_CAPTURE_COUNTER_TO_ZERO; |
| ppm_state = stPPM_SYNC; // next State |
| TRIGGER_INPUT_CAPTURE_INTERRUPT; |
| break; |
| } |
| sei (); |
| } |
| |
| int main (void) |
| { |
| cli (); // disable interrupts |
| |
| DDRA &= ~(1<<PPM_IN); // set Input Capture Pin as input |
| PORTA |= (1<<PPM_IN); // enable pullup |
| |
| DDRB |= (1<<PPM_OUT_PIN); // configure PPM_OUT pin as output |
| SET_PPM_OUT_LOW; // set low |
| |
| DDRA &= ~(1 << CHANNEL_9); // Channel 9 (Pin 10) input |
| PORTA |= (1 << CHANNEL_9); // enable pullup |
| |
| DDRA &= ~(1 << CHANNEL_10); // Channel 10 (Pin 9) input |
| PORTA |= (1 << CHANNEL_10); // enable pullup |
| |
| TCCR1A = ((0<<WGM11)|(0<<WGM10)); // CTC mode |
| TCCR1B = ((0<<WGM13)|(1<<WGM12)|(0<<CS12)|(1<<CS11)|(0<<CS10)); // CTC mode for COMPA, prescaler 8 / 8MHz => [1.0us] |
| |
| CLEAR_INPUT_CAPTURE_INTERRUPT_FLAG; // reset ICF flag |
| SET_COUNTER_TO_ZERO; |
| SET_COMPARE_COUNTER_TO_ZERO; |
| ENABLE_INPUT_CAPTURE; |
| DISABLE_OUTPUT_COMPARE; |
| RISING_EDGE_TRIGGER; |
| |
| sei (); // enable interrupts |
| |
| while(1); |
| } |