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// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + Copyright (c) Holger Buss, Ingo Busker
// + Nur für den privaten Gebrauch
// + www.MikroKopter.com
// + porting the sources to other systems or using the software on other systems (except hardware from www.mikrokopter.de) is not allowed
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// + 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 <avr/io.h>
#include <avr/interrupt.h>
#include <util/twi.h>
#include "main.h"
#include "eeprom.h"
#include "twimaster.h"
#include "fc.h"
#include "analog.h"

volatile uint8_t twi_state              = TWI_STATE_MOTOR_TX;
volatile uint8_t dac_channel    = 0;
volatile uint8_t motor_write    = 0;
volatile uint8_t motor_read     = 0;

volatile uint16_t I2CTimeout = 100;

uint8_t MissingMotor  = 0;


MotorData_t Motor[MAX_MOTORS];

#define SCL_CLOCK  200000L
#define I2C_TIMEOUT 30000

/**************************************************/
/*   Initialize I2C (TWI)                         */
/**************************************************/
void I2C_Init(void)
{
        uint8_t i;
        uint8_t sreg = SREG;
        cli();

        // SDA is INPUT
        DDRC  &= ~(1<<DDC1);
        // SCL is output
        DDRC |= (1<<DDC0);
        // pull up SDA
        PORTC |= (1<<PORTC0)|(1<<PORTC1);

        // TWI Status Register
        // prescaler 1 (TWPS1 = 0, TWPS0 = 0)
        TWSR &= ~((1<<TWPS1)|(1<<TWPS0));

        // set TWI Bit Rate Register
        TWBR = ((SYSCLK/SCL_CLOCK)-16)/2;

        twi_state               = TWI_STATE_MOTOR_TX;
        motor_write     = 0;
        motor_read              = 0;

        for(i=0; i < MAX_MOTORS; i++)
        {
                Motor[i].SetPoint       = 0;
                Motor[i].Present        = 0;
                Motor[i].Error          = 0;
                Motor[i].MaxPWM         = 0;
        }

        SREG = sreg;
}

/****************************************/
/*   Start I2C                          */
/****************************************/
void I2C_Start(uint8_t start_state)
{
        twi_state = start_state;
        // TWI Control Register
        // clear TWI interrupt flag (TWINT=1)
        // disable TWI Acknowledge Bit (TWEA = 0)
        // enable TWI START Condition Bit (TWSTA = 1), MASTER
        // disable TWI STOP Condition Bit (TWSTO = 0)
        // disable TWI Write Collision Flag (TWWC = 0)
        // enable i2c (TWEN = 1)
        // enable TWI Interrupt (TWIE = 1)
    TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN) | (1<<TWIE);
}

/****************************************/
/*    Stop I2C                          */
/****************************************/
void I2C_Stop(uint8_t start_state)
{
        twi_state = start_state;
        // TWI Control Register
        // clear TWI interrupt flag (TWINT=1)
        // disable TWI Acknowledge Bit (TWEA = 0)
        // diable TWI START Condition Bit (TWSTA = 1), no MASTER
        // enable TWI STOP Condition Bit (TWSTO = 1)
        // disable TWI Write Collision Flag (TWWC = 0)
        // enable i2c (TWEN = 1)
        // disable TWI Interrupt (TWIE = 0)
    TWCR = (1<<TWINT) | (1<<TWSTO) | (1<<TWEN);
}


/****************************************/
/*    Write to I2C                      */
/****************************************/
void I2C_WriteByte(int8_t byte)
{
        // move byte to send into TWI Data Register
        TWDR = byte;
        // clear interrupt flag (TWINT = 1)
        // enable i2c bus (TWEN = 1)
        // enable interrupt (TWIE = 1)
        TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE);
}


/****************************************/
/*    Receive byte and send ACK         */
/****************************************/
void I2C_ReceiveByte(void)
{
        TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE) | (1<<TWEA);
}

/****************************************/
/* I2C receive last byte and send no ACK*/
/****************************************/
void I2C_ReceiveLastByte(void)
{
        TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWIE);
}


/****************************************/
/*    Reset I2C                         */
/****************************************/
void I2C_Reset(void)
{
        // stop i2c bus
        I2C_Stop(TWI_STATE_MOTOR_TX);
        twi_state               = 0;
        motor_write     = TWDR;
        motor_write     = 0;
        motor_read              = 0;
        TWCR = (1<<TWINT); // reset to original state incl. interrupt flag reset
        TWAMR = 0;
        TWAR = 0;
        TWDR = 0;
        TWSR = 0;
        TWBR = 0;
        I2C_Init();
        I2C_Start(TWI_STATE_MOTOR_TX);
}


/****************************************/
/*        I2C ISR                       */
/****************************************/
ISR (TWI_vect)
{
        static uint8_t missing_motor    = 0;

    switch (twi_state++) // First i2c_start from SendMotorData()
        {
                // Master Transmit
        case 0: // TWI_STATE_MOTOR_TX
                        // skip motor if not used in mixer
                        while((Mixer.Motor[motor_write][MIX_GAS] <= 0) && (motor_write < MAX_MOTORS)) motor_write++;
                        if(motor_write >= MAX_MOTORS) // writing finished, read now
                        {
                                        motor_write = 0;
                                        twi_state = TWI_STATE_MOTOR_RX;
                                        I2C_WriteByte(0x53 + (motor_read * 2) ); // select slave adress in rx mode
                                }
                else I2C_WriteByte(0x52 + (motor_write * 2) ); // select slave adress in tx mode
                break;
        case 1: // Send Data to Slave
                                I2C_WriteByte(Motor[motor_write].SetPoint); // transmit rotation rate setpoint
                break;
        case 2: // repeat case 0+1 for all motors
                                if(TWSR == TW_MT_DATA_NACK) // Data transmitted, NACK received
                                {
                                        if(!missing_motor) missing_motor = motor_write + 1;
                                        if(++Motor[motor_write].Error == 0) Motor[motor_write].Error = 255; // increment error counter and handle overflow
                                }
                        I2C_Stop(TWI_STATE_MOTOR_TX);
                        I2CTimeout = 10;
                        motor_write++; // next motor
                I2C_Start(TWI_STATE_MOTOR_TX); // Repeated start -> switch slave or switch Master Transmit -> Master Receive
                break;
        // Master Receive Data
        case 3:
                        if(TWSR != TW_MR_SLA_ACK) //  SLA+R transmitted, if not ACK received
                        {       // no response from the addressed slave received
                                Motor[motor_read].Present = 0;
                                        motor_read++; // next motor
                                        if(motor_read >= MAX_MOTORS) motor_read = 0; // restart reading of first motor if we have reached the last one
                                        I2C_Stop(TWI_STATE_MOTOR_TX);
                                }
                else
                {
                                        Motor[motor_read].Present = ('1' - '-') + motor_read;
                                        I2C_ReceiveByte(); //Transmit 1st byte
                                }
                                MissingMotor = missing_motor;
                                missing_motor = 0;
                break;
        case 4: //Read 1st byte and transmit 2nd Byte
                                Motor[motor_read].Current = TWDR;
                                I2C_ReceiveLastByte(); // nack
                                break;
        case 5:
                //Read 2nd byte
                                Motor[motor_read].MaxPWM = TWDR;;
                                motor_read++; // next motor
                                if(motor_read >= MAX_MOTORS) motor_read = 0; // restart reading of first motor if we have reached the last one
                I2C_Stop(TWI_STATE_MOTOR_TX);
                break;

                // writing Gyro-Offsets
                case 7:
                                I2C_WriteByte(0x98); // Address the DAC
                                break;

                case 8:
                                I2C_WriteByte(0x10 + (dac_channel * 2)); // Select DAC Channel (0x10 = A, 0x12 = B, 0x14 = C)
                                break;

                case 9:
                                switch(dac_channel)
                                {
                                        case 0:
                                                        I2C_WriteByte(DacOffsetGyroNick); // 1st byte for Channel A
                                                        break;
                                        case 1:
                                                        I2C_WriteByte(DacOffsetGyroRoll); // 1st byte for Channel B
                                                        break;
                                        case 2:
                                                        I2C_WriteByte(DacOffsetGyroYaw ); // 1st byte for Channel C
                                                        break;
                                }
                                break;

                case 10:
                                I2C_WriteByte(0x80); // 2nd byte for all channels is 0x80
                                break;

                case 11:
                                I2C_Stop(TWI_STATE_MOTOR_TX);
                                I2CTimeout = 10;
                                // repeat case 7...10 until all DAC Channels are updated
                                if(dac_channel < 2)
                                {
                                        dac_channel ++;         // jump to next channel
                                        I2C_Start(TWI_STATE_GYRO_OFFSET_TX);            // start transmission for next channel
                                }
                                else
                                {       // data to last motor send
                                        dac_channel = 0; // reset dac channel counter
                                }
                break;

        default:
                I2C_Stop(TWI_STATE_MOTOR_TX);
                I2CTimeout = 10;
                motor_write = 0;
                motor_read = 0;
        }
}