trackswitch/main.c

#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/eeprom.h>
#include <stdlib.h>
#include <stdint.h>
#include <avr/pgmspace.h>

#include "main.h"

#include "driver/rs232.h"
#include "util/delay.h"


ISR ( USART_RXC_vect ) {
}

#define PULSE_PORT      PORTD
#define PULSE_BIT       PD2
#define RESPONSE_PORT   PORTD
#define RESPONSE_PIN    PD5
#define SOLENOID_A_PORT PORTB
#define SOLENOID_B_PORT PORTB

#define TRACKSWITCH_TYPE 2 // 1=double, 2=single

#define SOLENOID_A_PIN  PB1
#define SOLENOID_B_PIN  PB2

// internal analog comparator doesnt work well
//#define ANALOG_COMPARATOR       1

volatile uint16_t data = 0;
volatile uint8_t data_len = 0;
volatile uint8_t bitbuf_len = 0;
volatile uint16_t bitbuf = 0;
volatile uint8_t car_speed[8];
volatile uint8_t car_switch[8];
volatile uint16_t car0, car1;
volatile uint16_t car0_new, car0_old;
volatile uint16_t car1_new, car1_old;

volatile uint8_t response = 0;
uint8_t self_id = 2; // TODO - muss ermittelt werden und systemweit eindeutig sein

void send_response(uint16_t data) {
    /* frame format:
        1 startbit
        2 car id
        3 car id
        4 car id
        5 track change status bit 1
        6 track change status bit 2
        7 sender id
        8 sender id
        9 sender id
        9 sender id
        10 device type
        11 device type
        12 device type
        13 device type
        14 reserved
        15 reserved
        16 stopbit
    */
    uint8_t index = 16; // bit count maximum
    uint8_t enable = DDR(RESPONSE_PORT) | _BV(RESPONSE_PIN);
    uint8_t disable = DDR(RESPONSE_PORT) & ~_BV(RESPONSE_PIN);
    data |= 0b100000000000001; // make sure start/stop bits are set
    data = 0b1010101010101011;
    while (index != 0) {
        if ((data & 1) != 0) {
            DDR(RESPONSE_PORT) = enable; // enable response output
        } else {
            DDR(RESPONSE_PORT) = disable; // disable response output
        }
        data = data >> 1; // next bit prepare
        index--; // decrement index
        _delay_us(49); // bit valid phase
    }
    // finally be sure to release the bus!
    DDR(RESPONSE_PORT) = disable; // disable response output
}


ISR ( INT0_vect ) {
    GICR &= ~_BV(INT0) ; // Disable INT0
    // Startsignal erkannt, ab hier den Timer2 starten,
    // der liest dann alle 50µs den Zustand ein und schreibt das
    // empfangene Bit in den Puffer
    bitbuf = 0; // init
    bitbuf_len = 0b10000000; // init 1 pulse received
    TCNT2 = 0;
    TIMSK |= _BV(OCIE2); //enable timer2 interrupt
}

ISR ( TIMER2_COMP_vect ) {
    uint8_t clock;
    uint8_t state;
    uint8_t state2;
    if ((bitbuf_len & 0b10000000) == 0) clock = 0; else clock = 0xff;
    if ((bitbuf_len & 0b01000000) == 0) state = 0; else state = 0xff;
    if ((PIN(PULSE_PORT) & _BV(PULSE_BIT)) == 0) state2 = 0xff; else state2 = 0;

    if (clock) {
        bitbuf_len &= ~_BV(7); // switch clock to low
        // second pulse of bit
        if ((state==state2) & state2) {
            // two cycles high: packet end received
            data_len = (bitbuf_len & 0b00111111);
            TIMSK &= ~_BV(OCIE2); //disable timer2 interrupt
            GICR |= _BV(INT0) ; // Enable INT0

            //data = bitbuf; // output data
            // write data of controllers to array
            if (data_len == 10) { // controller data packet
                clock = (bitbuf >> 6) & 0b00000111;
                car_speed[clock] = (bitbuf >> 1) & 0x0F;
                car_switch[clock] = (bitbuf >> 5) & 1;
                // current response for this car?
                if (response != 0) {
                    if ( ((response & 0b00001110) >> 1) == clock) {
                        // add our ID to response:
                        send_response(response | self_id << 6);
                        response = 0;
                    }
                }
            }


        } else {
            bitbuf_len++; // increment bit counter
            bitbuf = bitbuf << 1; // shift bits
            if (state2 == 0) bitbuf |= 1; // receive logic one
        }
    } else {
        bitbuf_len |= _BV(7); // switch clock to high
        // first pulse of bit
        if (state2) {
            bitbuf_len |= _BV(6); // store new state
        } else {
            bitbuf_len &= ~_BV(6); // store new state
        }
    }
}


ISR (TIMER1_OVF_vect) {
    // reset both car counters to overflow
    car0_old = 0xffff;
    car1_old = 0xffff;
}

ISR (INT1_vect) {
    // car0 detector
    uint16_t tmp = 0;
    car0_new = TCNT1; // get current counter
    if (car0_old < car0_new) {
        // calculate difference
        if (car0 == 0) tmp = car0_new-car0_old;
        if ( (tmp > 54) && (tmp < 74) ) car0 = 1;
        if ( (tmp > 118) && (tmp < 138) ) car0 = 2;
        if ( (tmp > 186) && (tmp < 206) ) car0 = 3;
        if ( (tmp > 246) && (tmp < 266) ) car0 = 4;
    }
    car0_old = car0_new;
}

// ISR (TIMER1_CAPT_vect) {
#ifdef ANALOG_COMPARATOR
ISR (ANA_COMP_vect) {
    // car1 detector
    uint16_t tmp = 0;
    car1_new = TCNT1; // get current counter
    if (car1_old < car1_new) {
        // calculate difference
        if (car1 == 0) tmp = car1_new-car1_old;
        if ( (tmp > 50) && (tmp < 78) ) car1 = 1;
        if ( (tmp > 114) && (tmp < 146) ) car1 = 2;
        if ( (tmp > 183) && (tmp < 210) ) car1 = 3;
        if ( (tmp > 242) && (tmp < 270) ) car1 = 4;
    }
    car1_old = car1_new;
}
#else
// ALTERNATIV:
ISR (TIMER1_CAPT_vect) {
    // car1 detector
    uint16_t tmp = 0;
    car1_new = TCNT1; // get current counter
    if (car1_old < car1_new) {
        // calculate difference
        if (car1 == 0) tmp = car1_new-car1_old;
        if ( (tmp > 50) && (tmp < 78) ) car1 = 1;
        if ( (tmp > 114) && (tmp < 146) ) car1 = 2;
        if ( (tmp > 183) && (tmp < 210) ) car1 = 3;
        if ( (tmp > 242) && (tmp < 270) ) car1 = 4;
    }
    car1_old = car1_new;
}
#endif

void solenoid_delay(void) {
    _delay_ms(10);
}


int main(void)
{
    uint8_t car0_state, car1_state;

    // setup data bit timer2
    TCCR2 = (1<<CS21) | (1<<WGM21); //divide by 8, set compare match
    OCR2 = TIMER2_50US;

    // initialize timer1 for IR signal detection
#ifdef ANALOG_COMPARATOR
    TCCR1B = _BV(CS01) ; // 1mhz clock
    TIMSK = _BV(OCIE2) | _BV(TOIE1) ; //enable timer1+2
#else
    TCCR1B = _BV(CS01) | _BV(ICNC1) | _BV(ICES1); // 1mhz clock, enable ICP on rising edge
    TIMSK = _BV(OCIE2) | _BV(TOIE1) | _BV(TICIE1); //enable timer1+2 / ICP1
#endif

    // enable both external interrupts
    // int 0 = data RX
    // int 1 = car0 input
    MCUCR = _BV(ISC00) | _BV(ISC01) | _BV(ISC10) | _BV(ISC11); // INT0/1 rising edge
    GICR = _BV(INT0) | _BV(INT1) ; // Enable INT0 + INT1

#ifdef ANALOG_COMPARATOR
    ACSR = _BV(ACIE) | _BV(ACIS1) | _BV(ACIS0); // setup analog comparator
#endif

    // oscillator calibration
    // atmega8@1mhz = 0xac
    // @4mhz = ca 0xa0
    //OSCCAL = 0xa0;
    //OSCCAL = 0x9A;
    //OSCCAL = 0xa0; // internal oscillator @ 4 mhz.... doesnt work accurate!

    RS232_init(); // initialize RS232 interface
    RS232_puts_p(PSTR("Freeslot TrackSwitch v1.2\n"));
    sei();


    DDR(SOLENOID_A_PORT) |= _BV(SOLENOID_A_PIN);
    DDR(SOLENOID_B_PORT) |= _BV(SOLENOID_B_PIN);

    DDR(RESPONSE_PORT) &= ~_BV(RESPONSE_PIN); // switch response off
    RESPONSE_PORT &= ~_BV(RESPONSE_PIN); // switch response off

    while (1) {
        // main loop

    /*
        0 = AA
        1 = AB
        2 = BB
        3 = BA
    */
        if (car0 != car0_state) {
            car0_state = car0;
            if ( (car0_state != 0) && (car_switch[car0_state-1] == 0) && (car_speed[car0_state-1]>0) ) {
                response = (1 | ((car0_state-1)<<1) | (1 << 4));
                // trigger solenoid A
                RS232_putc('A');
                RS232_putc('B');
                RS232_putc('0'+car0_state);
                RS232_putc('\n');

                SOLENOID_A_PORT |= _BV(SOLENOID_A_PIN);
                solenoid_delay();
                SOLENOID_A_PORT &= ~_BV(SOLENOID_A_PIN);
                solenoid_delay();
            }
            if (car0_state != 0) {
                response = (1 | ((car0_state-1)<<1));
                RS232_putc('A');
                RS232_putc('A');
                RS232_putc('0'+car0_state);
                RS232_putc('\n');
            }
        } car0 = 0;


        if (car1 != car1_state) {
            car1_state = car1;
            if ( (car1_state != 0) && (car_switch[car1_state-1] == 0) && (car_speed[car1_state-1]>0) ) {
                response = (1 | ((car1_state-1)<<1) | (3 << 4));
                // trigger solenoid B
                RS232_putc('B');
                RS232_putc('A');
                RS232_putc('0'+car1_state);
                RS232_putc('\n');

                SOLENOID_B_PORT |= _BV(SOLENOID_B_PIN);
                solenoid_delay();
                SOLENOID_B_PORT &= ~_BV(SOLENOID_B_PIN);
                solenoid_delay();
            }
            if (car1_state != 0) {
                response = (1 | ((car1_state-1)<<1) | (2 << 4));
                RS232_putc('B');
                RS232_putc('B');
                RS232_putc('0'+car1_state);
                RS232_putc('\n');
            }
        } car1 = 0;


    } // main loop end
};