Subversion Repositories MK3Mag

/*#######################################################################################

MK3Mag 3D-Magnet sensor

!!! THIS IS NOT FREE SOFTWARE !!!

#######################################################################################*/

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// + Copyright (c) 05.2008 Holger Buss

// + Thanks to Ilja Fähnrich (P_Latzhalter)

// + Nur für den privaten Gebrauch

// + www.MikroKopter.com

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur

// + mit unserer Zustimmung zulässig

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// + 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.

// + AUSNAHME: Ein bei www.mikrokopter.de erworbener vorbestückter MK3Mag darf als Baugruppe auch in kommerziellen Systemen verbaut werden

// + Im Zweifelsfall bitte anfragen bei: info@mikrokopter.de

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// + 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 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.

// +   * PORTING this software (or parts of it) to systems (other than hardware from www.mikrokopter.de) is NOT allowed

// +   * 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

// +     Exception: A preassembled MK3Mag, purchased from www.mikrokopter.de may be used as a part of commercial systems

// +     In case of doubt please contact: info@MikroKopter.de

// +   * If sources or documentations are redistributet on other webpages, our webpage (http://www.MikroKopter.de) must be

// +     clearly linked as origin

// +  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 "twislave.h"

#include "uart.h"

#include "main.h"

#include "timer0.h"

#include "led.h"

volatile uint8_t I2C_RxBufferSize = 0, I2C_TxBufferSize = 0;

volatile uint8_t *I2C_TxBuffer = 0, *I2C_RxBuffer = 0;

volatile uint8_t Tx_Idx = 0, Rx_Idx = 0;

struct I2C_Heading_t       I2C_Heading;

struct I2C_WriteAttitude_t I2C_WriteAttitude;

struct I2C_Mag_t           I2C_Mag;

struct I2C_Version_t       I2C_Version;

struct I2C_WriteCal_t      I2C_WriteCal;

void I2C_Init(void)

{

        uint8_t sreg;

        // backup status register

        sreg = SREG;

    // disable global interrupts

        cli();

        // SCK/SCL and  MISO/SDA are at put together on the same connector pin in the schematic

        // set PB4 (SCK) and PB5 (MISO) as input pull up

        DDRB &= ~((1<<DDB4)|(1<<DDB5));

        PORTB |= ((1<<PORTB4)|(1<<PORTB5));

        // set PC4 (SDA) and PC5 (SCL) as input tristate

        DDRC &= ~((1<<DDC4)|(1<<DDC5));

        PORTC &= ~((1<<PORTC4)|(1<<PORTC5));

        I2C_TxBuffer = 0;

        Tx_Idx = 0;

        I2C_TxBufferSize = 0;

        I2C_RxBuffer = 0;

        Rx_Idx = 0;

        I2C_RxBufferSize = 0;

        TWCR &= ~(1<<TWSTA)|(1<<TWSTO);

        TWCR|= (1<<TWEA) | (1<<TWEN)|(1<<TWIE);

        // set own address

        // set own address in the upper 7 bits

    TWAR = I2C_SLAVE_ADDRESS; // set own address only the upper 7 bits are relevant

        // TWI Control Register

        // enable TWI Acknowledge Bit (TWEA = 1)

        // disable TWI START Condition Bit (TWSTA = 0), SLAVE

        // disable TWI  STOP Condition Bit (TWSTO = 0), SLAVE

        // enable TWI (TWEN = 1)

        // enable TWI Interrupt (TWIE = 1)

        TWCR |= (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC);

        // update version info

        I2C_Version.Major = VERSION_MAJOR;

        I2C_Version.Minor = VERSION_MINOR;

        I2C_Version.Compatible = I2C_PROTOCOL_COMP;

        // resore status register

        SREG = sreg;

}

// send ACK after recieving a byte / ACK is expected after transmitting a byte

#define TWCR_ACK TWCR           = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC)

// send no ACK after recieving a byte / No ACK is expected after transmitting a byte

#define TWCR_NACK TWCR          = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC)

// switched to the non adressed slave mode

#define TWCR_RESET TWCR         = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|(0<<TWWC)

// The bit pattern for TWCR_ACK and TWCR_RESET are equal. This is no errro but used for better understanding.

#define TWCR_CLEARBUS TWCR      = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC)

ISR (TWI_vect)

{

        uint8_t data;

        // check event

        switch (TW_STATUS)

        {

        case TW_SR_SLA_ACK: // slave addressed in receiver mode and ack has been returned

            Rx_Idx = 0xFF;  // reset rx buffer pointer

                        TWCR_ACK;       // trigger receiving of first data byte and send ack afterwards

                        LED_GRN_TOGGLE;

            return;

        case TW_SR_DATA_ACK: // data has been received and ack has been returned

                data = TWDR;

                        if (Rx_Idx  == 0xFF)

                        {       // if the fisrt byte after slave addressing was received

                                switch(data)

                                {

                                        case I2C_CMD_VERSION:

                                                I2C_TxBuffer = (uint8_t *)&I2C_Version;

                                                I2C_TxBufferSize = sizeof(I2C_Version);

                                                I2C_RxBuffer = 0;

                                                I2C_RxBufferSize = 0;

                                                break;

                                        case I2C_CMD_WRITE_CAL:

                                                I2C_TxBuffer = 0;

                                                I2C_TxBufferSize = 0;

                                                I2C_RxBuffer = (uint8_t *)&I2C_WriteCal;

                                                I2C_RxBufferSize = sizeof(I2C_WriteCal);

                                                break;

                                        case I2C_CMD_READ_MAG:

                                                I2C_TxBuffer = (uint8_t *)&I2C_Mag;

                                                I2C_TxBufferSize = sizeof(I2C_Mag);

                                                I2C_RxBuffer = 0;

                                                I2C_RxBufferSize = 0;

                                                I2C_Mag.MagX = MagnetX;

                                                I2C_Mag.MagY = MagnetY;

                                                I2C_Mag.MagZ = MagnetZ;

                                                break;

                                        case I2C_CMD_READ_HEADING:

                                                I2C_TxBuffer = (uint8_t *)&I2C_Heading;

                                                I2C_TxBufferSize = sizeof(I2C_Heading);

                                                I2C_RxBuffer =  (uint8_t *)&I2C_WriteAttitude;

                                                I2C_RxBufferSize = sizeof(I2C_WriteAttitude);

                                                // update heading from global variable

                                                I2C_Heading.Heading = Heading;

                                                // copy current attitude from I2C rx buffer to uart rx buffer (this is used for the calulation of the heading)

                                                ExternData.Attitude[NICK] = I2C_WriteAttitude.Nick;

                                                ExternData.Attitude[ROLL] = I2C_WriteAttitude.Roll;

                                                break;

                                        default: // unknown command id

                                                I2C_RxBuffer = 0;

                                                I2C_RxBufferSize = 0;

                                                I2C_TxBuffer = 0;

                                                I2C_TxBufferSize = 0;

                                        break;

                                }

                                Rx_Idx = 0; // set rx buffer index to start of the buffer

                        }

                        else // Rx_Idx  != 0xFF

                        {

                                // fill receiver buffer with the byte that has been received

                                // if buffer exist and there is still some free space

                                if((I2C_RxBuffer != 0) && (Rx_Idx  < I2C_RxBufferSize))

                                {

                                        I2C_RxBuffer[Rx_Idx++] = data;

                                }

                                // else ignore the data

                        }

                        TWCR_ACK;

            return;

        case TW_ST_SLA_ACK: // slave transmitter selected

                // reset index  to start of tx buffer

            Tx_Idx = 0;

            // if tx bufer exist and there is at least ine byte to transfer

                        if((I2C_TxBuffer != 0) && (I2C_TxBufferSize > 1))

                        {

                                TWDR = I2C_TxBuffer[Tx_Idx++];

                        }

                        else

                        {   // send 0x00 if no tx buffer exist or all bytes of the tx buffer have been transmitted

                                TWDR = 0x00;

                        }

                        TWCR_ACK;

            return;

                case TW_ST_DATA_ACK: // data byte has been transmitted ack has been received

                        // put next byte from tx buffer to the data register

                        if((I2C_TxBuffer != 0) && (Tx_Idx < I2C_TxBufferSize))

                        {

                        TWDR = I2C_TxBuffer[Tx_Idx++];

                        }

                        else

                        {   // send dummy byte instead

                                TWDR = 0x00;

                        }

                        TWCR_ACK;

            return;

        case TW_BUS_ERROR:  // Bus-Error

            TWCR_CLEARBUS;      // free bus, reset to nonselected slave

            return;

                case TW_ST_DATA_NACK:   // data transmitted, NACK received

                case TW_ST_LAST_DATA:   // last data byte transmitted, ACK received

                case TW_SR_STOP:                // stop or repeated start condition received while selected

                default:

                        TWCR_RESET; // switch to the not addressed slave mode, own SLA will be recognized

                return;

        }

}