ardupilot/libraries/APM_RC/APM_RC_APM1.cpp

/*
 *       APM_RC_APM1.cpp - Radio Control Library for Ardupilot Mega. Arduino
 *       Code by Jordi Mu<EFBFBD>oz and Jose Julio. DIYDrones.com
 *
 *       This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *       RC Input : PPM signal on IC4 pin
 *       RC Output : 11 Servo outputs (standard 20ms frame)
 *
 *       Methods:
 *               Init() : Initialization of interrupts an Timers
 *               OutpuCh(ch,pwm) : Output value to servos (range : 900-2100us) ch=0..10
 *               InputCh(ch) : Read a channel input value.  ch=0..7
 *               GetState() : Returns the state of the input. 1 => New radio frame to process
 *                            Automatically resets when we call InputCh to read channels
 *
 */
#include "APM_RC_APM1.h"

#include <avr/interrupt.h>
#if defined(ARDUINO) && ARDUINO >= 100
 #include "Arduino.h"
#else
 #include "WProgram.h"
#endif

#if !defined(__AVR_ATmega1280__) && !defined(__AVR_ATmega2560__) && !defined(DESKTOP_BUILD)
 # error Please check the Tools/Board menu to ensure you have selected Arduino Mega as your target.
#else

// Variable definition for Input Capture interrupt
volatile uint16_t APM_RC_APM1::_PWM_RAW[NUM_CHANNELS] = {2400,2400,2400,2400,2400,2400,2400,2400};
volatile uint8_t APM_RC_APM1::_radio_status=0;

/****************************************************
*   Input Capture Interrupt ICP4 => PPM signal read
****************************************************/
void APM_RC_APM1::_timer4_capt_cb(void)
{
    static uint16_t ICR4_old;
    static uint8_t PPM_Counter=0;

    uint16_t Pulse;
    uint16_t Pulse_Width;

    Pulse=ICR4;
    if (Pulse<ICR4_old) {                     // Take care of the overflow of Timer4 (TOP=40000)
        Pulse_Width=(Pulse + 40000)-ICR4_old; // Calculating pulse
    }
    else {
        Pulse_Width=Pulse-ICR4_old;           // Calculating pulse
    }

    if (Pulse_Width>8000) {                   // SYNC pulse?
        // pass through values if at least a minimum number of channels received
        if( PPM_Counter >= MIN_CHANNELS ) {
            _radio_status = 1;
            _ppm_count++;
        }
        PPM_Counter=0;
    }
    else {
        if (PPM_Counter < NUM_CHANNELS) {     // Valid pulse channel?
            _PWM_RAW[PPM_Counter++]=Pulse_Width;   // Saving pulse.
        }
    }
    ICR4_old = Pulse;
}


// Constructors ////////////////////////////////////////////////////////////////

APM_RC_APM1::APM_RC_APM1()
{
}

// Public Methods //////////////////////////////////////////////////////////////
void APM_RC_APM1::Init( Arduino_Mega_ISR_Registry * isr_reg )
{

    isr_reg->register_signal(ISR_REGISTRY_TIMER4_CAPT, _timer4_capt_cb );

    // Init PWM Timer 1
    pinMode(11,OUTPUT); //OUT9 (PB5/OC1A)
    pinMode(12,OUTPUT); //OUT2 (PB6/OC1B)
    pinMode(13,OUTPUT); //OUT3 (PB7/OC1C)

    //Remember the registers not declared here remains zero by default...
    TCCR1A =((1<<WGM11)); //Please read page 131 of DataSheet, we are changing the registers settings of WGM11,COM1B1,COM1A1 to 1 thats all...
    TCCR1B = (1<<WGM13)|(1<<WGM12)|(1<<CS11); //Prescaler set to 8, that give us a resolution of 0.5us, read page 134 of data sheet
    OCR1A = 0xFFFF; // Init ODR registers to nil output signal
    OCR1B = 0xFFFF;
    OCR1C = 0xFFFF;
    ICR1 = 40000; //50hz freq...Datasheet says  (system_freq/prescaler)/target frequency. So (16000000hz/8)/50hz=40000,

    // Init PWM Timer 3
    pinMode(2,OUTPUT); //OUT7 (PE4/OC3B)
    pinMode(3,OUTPUT); //OUT6 (PE5/OC3C)
    pinMode(5,OUTPUT); //OUT10(PE3/OC3A)
    TCCR3A =((1<<WGM31));
    TCCR3B = (1<<WGM33)|(1<<WGM32)|(1<<CS31);
    OCR3A = 0xFFFF; // Init ODR registers to nil output signal
    OCR3B = 0xFFFF;
    OCR3C = 0xFFFF;
    ICR3 = 40000; //50hz freq

    // Init PWM Timer 5
    pinMode(44,OUTPUT); //OUT1 (PL5/OC5C)
    pinMode(45,OUTPUT); //OUT0 (PL4/OC5B)
    pinMode(46,OUTPUT); //OUT8 (PL3/OC5A)

    TCCR5A =((1<<WGM51));
    TCCR5B = (1<<WGM53)|(1<<WGM52)|(1<<CS51);
    OCR5A = 0xFFFF; // Init ODR registers to nil output signal
    OCR5B = 0xFFFF;
    OCR5C = 0xFFFF;
    ICR5 = 40000; //50hz freq

    // Init PPM input and PWM Timer 4
    pinMode(49, INPUT); // ICP4 pin (PL0) (PPM input)
    pinMode(7,OUTPUT); //OUT5 (PH4/OC4B)
    pinMode(8,OUTPUT); //OUT4 (PH5/OC4C)

    TCCR4A =((1<<WGM40)|(1<<WGM41));
    //Prescaler set to 8, that give us a resolution of 0.5us
    // Input Capture rising edge
    TCCR4B = ((1<<WGM43)|(1<<WGM42)|(1<<CS41)|(1<<ICES4));
    OCR4B = 0xFFFF; // Init OCR registers to nil output signal
    OCR4C = 0xFFFF;
    OCR4A = 40000; ///50hz freq.

    //TCCR4B |=(1<<ICES4); //Changing edge detector (rising edge).
    //TCCR4B &=(~(1<<ICES4)); //Changing edge detector. (falling edge)
    TIMSK4 |= (1<<ICIE4); // Enable Input Capture interrupt. Timer interrupt mask
}

void APM_RC_APM1::OutputCh(uint8_t ch, uint16_t pwm)
{
    pwm=constrain(pwm,MIN_PULSEWIDTH,MAX_PULSEWIDTH);
    pwm<<=1; // pwm*2;

    switch(ch)
    {
    case 0:  OCR5B=pwm; break;  //ch1
    case 1:  OCR5C=pwm; break;  //ch2
    case 2:  OCR1B=pwm; break;  //ch3
    case 3:  OCR1C=pwm; break;  //ch4
    case 4:  OCR4C=pwm; break;  //ch5
    case 5:  OCR4B=pwm; break;  //ch6
    case 6:  OCR3C=pwm; break;  //ch7
    case 7:  OCR3B=pwm; break;  //ch8
    case 8:  OCR5A=pwm; break;  //ch9,  PL3
    case 9:  OCR1A=pwm; break;  //ch10, PB5
    case 10: OCR3A=pwm; break;  //ch11, PE3
    }
}

uint16_t APM_RC_APM1::OutputCh_current(uint8_t ch)
{
    uint16_t pwm=0;
    switch(ch) {
    case 0:  pwm=OCR5B; break;      //ch1
    case 1:  pwm=OCR5C; break;      //ch2
    case 2:  pwm=OCR1B; break;      //ch3
    case 3:  pwm=OCR1C; break;      //ch4
    case 4:  pwm=OCR4C; break;      //ch5
    case 5:  pwm=OCR4B; break;      //ch6
    case 6:  pwm=OCR3C; break;      //ch7
    case 7:  pwm=OCR3B; break;      //ch8
    case 8:  pwm=OCR5A; break;      //ch9,  PL3
    case 9:  pwm=OCR1A; break;      //ch10, PB5
    case 10: pwm=OCR3A; break;      //ch11, PE3
    }
    return pwm>>1;
}

void APM_RC_APM1::enable_out(uint8_t ch)
{
    switch(ch) {
    case 0:  TCCR5A |= (1<<COM5B1); break;  // CH_1 : OC5B
    case 1:  TCCR5A |= (1<<COM5C1); break;  // CH_2 : OC5C
    case 2:  TCCR1A |= (1<<COM1B1); break;  // CH_3 : OC1B
    case 3:  TCCR1A |= (1<<COM1C1); break;  // CH_4 : OC1C
    case 4:  TCCR4A |= (1<<COM4C1); break;  // CH_5 : OC4C
    case 5:  TCCR4A |= (1<<COM4B1); break;  // CH_6 : OC4B
    case 6:  TCCR3A |= (1<<COM3C1); break;  // CH_7 : OC3C
    case 7:  TCCR3A |= (1<<COM3B1); break;  // CH_8 : OC3B
    case 8:  TCCR5A |= (1<<COM5A1); break;  // CH_9 : OC5A
    case 9:  TCCR1A |= (1<<COM1A1); break;  // CH_10: OC1A
    case 10: TCCR3A |= (1<<COM3A1); break;  // CH_11: OC3A
    }
}

void APM_RC_APM1::disable_out(uint8_t ch)
{
    switch(ch) {
    case 0:  TCCR5A &= ~(1<<COM5B1); break;  // CH_1 : OC5B
    case 1:  TCCR5A &= ~(1<<COM5C1); break;  // CH_2 : OC5C
    case 2:  TCCR1A &= ~(1<<COM1B1); break;  // CH_3 : OC1B
    case 3:  TCCR1A &= ~(1<<COM1C1); break;  // CH_4 : OC1C
    case 4:  TCCR4A &= ~(1<<COM4C1); break;  // CH_5 : OC4C
    case 5:  TCCR4A &= ~(1<<COM4B1); break;  // CH_6 : OC4B
    case 6:  TCCR3A &= ~(1<<COM3C1); break;  // CH_7 : OC3C
    case 7:  TCCR3A &= ~(1<<COM3B1); break;  // CH_8 : OC3B
    case 8:  TCCR5A &= ~(1<<COM5A1); break;  // CH_9 : OC5A
    case 9:  TCCR1A &= ~(1<<COM1A1); break;  // CH_10: OC1A
    case 10: TCCR3A &= ~(1<<COM3A1); break;  // CH_11: OC3A
    }
}

uint16_t APM_RC_APM1::InputCh(uint8_t ch)
{
    uint16_t result;

    if (_HIL_override[ch] != 0) {
        return _HIL_override[ch];
    }

    // We need to block ICP4 interrupts during the read of 16 bit PWM values
    uint8_t _timsk4 = TIMSK4;
    TIMSK4 &= ~(1<<ICIE4);

    // value
    result = _PWM_RAW[ch];

   // Enable ICP4 interrupt if previously active
    TIMSK4 = _timsk4;

    // Because timer runs at 0.5us we need to do value/2
    result >>= 1;

    // Limit values to a valid range
    result = constrain(result,MIN_PULSEWIDTH,MAX_PULSEWIDTH);
    _radio_status = 0;     // Radio channel read
    return result;
}

uint8_t APM_RC_APM1::GetState(void)
{
    return(_radio_status);
}


// InstantPWM implementation
void APM_RC_APM1::Force_Out(void)
{
    Force_Out0_Out1();
    Force_Out2_Out3();
    Force_Out6_Out7();
}
// This function forces the PWM output (reset PWM) on Out0 and Out1 (Timer5). For quadcopters use
void APM_RC_APM1::Force_Out0_Out1(void)
{
    if (TCNT5>5000) // We take care that there are not a pulse in the output
        TCNT5=39990;  // This forces the PWM output to reset in 5us (10 counts of 0.5us). The counter resets at 40000
}
// This function forces the PWM output (reset PWM) on Out2 and Out3 (Timer1). For quadcopters use
void APM_RC_APM1::Force_Out2_Out3(void)
{
    if (TCNT1>5000)
        TCNT1=39990;
}
// This function forces the PWM output (reset PWM) on Out6 and Out7 (Timer3). For quadcopters use
void APM_RC_APM1::Force_Out6_Out7(void)
{
    if (TCNT3>5000)
        TCNT3=39990;
}

/* --------------------- OUTPUT SPEED CONTROL --------------------- */

void APM_RC_APM1::SetFastOutputChannels(uint32_t chmask, uint16_t speed_hz)
{
    uint16_t icr = _map_speed(speed_hz);

    if ((chmask & ( _BV(CH_1) | _BV(CH_2) | _BV(CH_9))) != 0) {
        ICR5 = icr;
    }

    if ((chmask & ( _BV(CH_3) | _BV(CH_4) | _BV(CH_10))) != 0) {
        ICR1 = icr;
    }

 #if 0
    if ((chmask & ( _BV(CH_5) | _BV(CH_6))) != 0) {
        /* These channels intentionally left blank:
         * Can't change output speed of ch5 (OCR4B) and ch6 (OCR4C).
         * Timer 4 period controlled by OCR4A, and used for input
         * capture on ICR4.
         * If the period of Timer 4 must be changed, the input capture
         * code will have to be adjusted as well
         */
    }
 #endif

    if ((chmask & ( _BV(CH_7) | _BV(CH_8) | _BV(CH_11))) != 0) {
        ICR3 = icr;
    }

}

// allow HIL override of RC values
// A value of -1 means no change
// A value of 0 means no override, use the real RC values
bool APM_RC_APM1::setHIL(int16_t v[NUM_CHANNELS])
{
    uint8_t sum = 0;
    for (uint8_t i=0; i<NUM_CHANNELS; i++) {
        if (v[i] != -1) {
            _HIL_override[i] = v[i];
        }
        if (_HIL_override[i] != 0) {
            sum++;
        }
    }
    _radio_status = 1;
    _last_update = millis();
    if (sum == 0) {
        return 0;
    } else {
        return 1;
    }
}

void APM_RC_APM1::clearOverride(void)
{
    for (uint8_t i=0; i<NUM_CHANNELS; i++) {
        _HIL_override[i] = 0;
    }
}


#endif // defined(ATMega1280)