| 0,0 → 1,164 |
|---|
| #include <avr/io.h> |
| #include <avr/interrupt.h> |
| #include <util/twi.h> |
| #include <util/delay.h> |
| //#include "eeprom.h" |
| #include "twimaster.h" |
| //#include "analog.h" |
| #include "configuration.h" |
| |
| volatile uint8_t twi_state = TWI_STATE_IDLE; |
| volatile uint8_t dac_channel = 0; |
| volatile uint16_t I2CTimeout = 100; |
| volatile uint8_t DACValues[4]; |
| uint8_t DACChannel = 0; |
| |
| #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_IDLE; |
| 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_IDLE); |
| TWCR = (1 << TWINT); // reset to original state incl. interrupt flag reset |
| TWAMR = 0; |
| TWAR = 0; |
| TWDR = 0; |
| TWSR = 0; |
| TWBR = 0; |
| I2C_init(); |
| } |
| |
| /**************************************** |
| * I2C ISR |
| ****************************************/ |
| ISR (TWI_vect) |
| { |
| switch (twi_state) { // First i2c_start from SendMotorData() |
| case 0: break; |
| |
| // Writing ADC values. |
| case 7: |
| twi_state++; |
| I2C_WriteByte(0x98); // Address the DAC |
| break; |
| |
| case 8: |
| twi_state++; |
| I2C_WriteByte(0x10 + (DACChannel << 1)); // Select DAC Channel (0x10 = A, 0x12 = B, 0x14 = C) |
| break; |
| |
| case 9: |
| twi_state++; |
| I2C_WriteByte(DACValues[DACChannel]); |
| break; |
| |
| case 10: |
| twi_state++; |
| I2C_WriteByte(0x80); // 2nd byte for all channels is 0x80 |
| break; |
| |
| case 11: |
| twi_state++; |
| I2C_Stop(TWI_STATE_IDLE); |
| I2CTimeout = 10; |
| // repeat case 7...10 until all DAC Channels are updated |
| if (DACChannel < 2) { |
| DACChannel++; // jump to next channel |
| I2C_Start(TWI_STATE_GYRO_OFFSET_TX); // start transmission for next channel |
| } else { |
| DACChannel = 0; // reset dac channel counter |
| } |
| break; |
| |
| default: |
| I2C_Stop(TWI_STATE_IDLE); |
| I2CTimeout = 10; |
| } |
| } |