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/*############################################################################
############################################################################*/
#include <avr/io.h>
#include <avr/interrupt.h>
#include "main.h"
#include "twimaster.h"
#include "fc.h"
#include "analog.h"
volatile uint8_t twi_state = 0;
volatile uint8_t motor_write = 0;
volatile uint8_t motor_read = 0;
volatile uint8_t dac_channel = 0;
volatile uint8_t motor_rx[MOTOR_COUNT*2];
volatile uint16_t I2CTimeout = 100;
#define SCL_CLOCK 200000L
#define I2C_TIMEOUT 30000
#define TWSR_STATUS_MASK 0xF8
// for Master Transmitter Mode
#define I2C_STATUS_START 0x08
#define I2C_STATUS_REPEATSTART 0x10
#define I2C_STATUS_TX_SLA_ACK 0x18
#define I2C_STATUS_SLAW_NOACK 0x20
#define I2C_STATUS_TX_DATA_ACK 0x28
#define I2C_STATUS_TX_DATA_NOTACK 0x30
#define I2C_STATUS_RX_DATA_ACK 0x50
#define I2C_STATUS_RX_DATA_NOTACK 0x58
/**************************************************/
/* Initialize I2C (TWI) */
/**************************************************/
void I2C_Init(void)
{
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 = 0;
motor_write = 0;
motor_read = 0;
SREG = sreg;
}
/****************************************/
/* Start I2C */
/****************************************/
void I2C_Start(void)
{
// 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(void)
{
// 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 = 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();
I2C_WriteByte(0);
}
/****************************************/
/* I2C ISR */
/****************************************/
ISR (TWI_vect)
{
switch (twi_state++) // First i2c_start from SendMotorData()
{
// Master Transmit
case 0: // Send SLA-W
I2C_WriteByte(0x52 + (motor_write * 2) );
break;
case 1: // Send Data to Slave
#ifdef HEXAKOPTER
switch(motor_write)
{
case 0:
I2C_WriteByte(Motor_FrontLeft);
break;
case 1:
I2C_WriteByte(Motor_RearRight);
break;
case 2:
I2C_WriteByte(Motor_FrontRight);
break;
case 3:
I2C_WriteByte(Motor_RearLeft);
break;
case 4:
I2C_WriteByte(Motor_Right);
break;
case 5:
I2C_WriteByte(Motor_Left);
break;
}
#else
switch(motor_write)
{
case 0:
I2C_WriteByte(Motor_Front);
break;
case 1:
I2C_WriteByte(Motor_Rear);
break;
case 2:
I2C_WriteByte(Motor_Right);
break;
case 3:
I2C_WriteByte(Motor_Left);
break;
}
#endif
break;
case 2: // repeat case 0+1 for all motors
I2C_Stop();
if (motor_write < (MOTOR_COUNT-1))
{
motor_write++; // jump to next motor
twi_state = 0; // and repeat from state 0
}
else
{ // data to last motor send
motor_write = 0; // reset motor write counter
}
I2C_Start(); // Repeated start -> switch slave or switch Master Transmit -> Master Receive
break;
// Master Receive
case 3: // Send SLA-R
I2C_WriteByte(0x53 + (motor_read * 2) );
break;
case 4:
//Transmit 1st byte
I2C_ReceiveByte();
break;
case 5: //Read 1st byte and transmit 2nd Byte
motor_rx[motor_read] = TWDR;
I2C_ReceiveLastByte();
break;
case 6:
//Read 2nd byte
motor_rx[motor_read + 4] = TWDR;
motor_read++;
if (motor_read > (MOTOR_COUNT-1)) motor_read = 0;
I2C_Stop();
twi_state = 0;
I2CTimeout = 10;
break;
// 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(AnalogOffsetNick); // 1st byte for Channel A
break;
case 1:
I2C_WriteByte(AnalogOffsetRoll); // 1st byte for Channel B
break;
case 2:
I2C_WriteByte(AnalogOffsetYaw ); // 1st byte for Channel C
break;
}
break;
case 10:
I2C_WriteByte(0x80); // 2nd byte for all channels is 0x80
break;
case 11:
I2C_Stop();
I2CTimeout = 10;
// repeat case 7...10 until all DAC Channels are updated
if(dac_channel < 2)
{
dac_channel ++; // jump to next channel
twi_state = 7; // and repeat from state 7
I2C_Start(); // start transmission for next channel
}
else
{ // data to last motor send
dac_channel = 0; // reset dac channel counter
twi_state = 0; // reset twi_state
}
break;
default:
I2C_Stop();
twi_state = 0;
I2CTimeout = 10;
motor_write = 0;
motor_read = 0;
}
}