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/*#######################################################################################
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;
static uint8_t crc;
// 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
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
crc = data;
}
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;
crc += data;
}
else if (Rx_Idx == I2C_RxBufferSize) // crc byte was transferred
{
if(crc == data)
{
// copy primary rx buffer to target
}
}
// else ignore data
Rx_Idx++;
}
TWCR_ACK;
return;
case TW_ST_SLA_ACK: // slave transmitter selected
// reset index to start of tx buffer
Tx_Idx = 0;
crc = 0;
// if tx buffer exist and there is at least one byte to transfer
if((I2C_TxBuffer != 0) && (I2C_TxBufferSize > 1))
{
data = I2C_TxBuffer[Tx_Idx];
}
else
{ // send 0x00 if no tx buffer exist or all bytes of the tx buffer have been transmitted
data = 0x00;
}
crc += data;
Tx_Idx++;
TWDR = data;
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))
{
data = I2C_TxBuffer[Tx_Idx];
crc += data;
}
else if (Tx_Idx == I2C_TxBufferSize)
{ // send crc byte at the end
data = crc;
}
else
{
data = 0x00;
}
Tx_Idx++;
TWDR = data;
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;
}
}