64,18 → 64,17 |
#include "led.h" |
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uint8_t I2C_RxBufferSize = 0, I2C_TxBufferSize = 0; |
uint8_t *I2C_TxBuffer = 0, *I2C_RxBuffer = 0; |
uint8_t Tx_Idx = 0, Rx_Idx = 0; |
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; |
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I2C_Heading_t I2C_Heading; |
I2C_WriteAttitude_t I2C_WriteAttitude; |
I2C_Mag_t I2C_Mag; |
I2C_EEPROM_t I2C_ReadEEPROM, I2C_WriteEEPROM; |
I2C_Version_t I2C_Version; |
I2C_WriteCal_t I2C_WriteCal; |
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; |
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void I2C_Init(void) |
90,9 → 89,9 |
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// SCK/SCL and MISO/SDA are at put together on the same connector pin in the schematic |
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// set PB4 (SCK) and PB5 (MISO) as input tristate |
// set PB4 (SCK) and PB5 (MISO) as input pull up |
DDRB &= ~((1<<DDB4)|(1<<DDB5)); |
PORTB &= ~((1<<PORTB4)|(1<<PORTB5)); |
PORTB |= ((1<<PORTB4)|(1<<PORTB5)); |
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// set PC4 (SDA) and PC5 (SCL) as input tristate |
DDRC &= ~((1<<DDC4)|(1<<DDC5)); |
119,9 → 118,7 |
// disable TWI STOP Condition Bit (TWSTO = 0), SLAVE |
// enable TWI (TWEN = 1) |
// enable TWI Interrupt (TWIE = 1) |
TWCR &= ~((1<<TWSTA)|(1<<TWSTO)); |
TWCR |= (1<<TWEA)|(1<<TWEN)|(1<<TWIE); |
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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; |
138,11 → 135,12 |
// 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<<TWEA) | (1<<TWSTO) | (1<<TWINT) | (1<<TWEN) | (1<<TWIE) |
#define TWCR_CLEARBUS TWCR = (1<<TWEN)|(1<<TWIE)|(1<<TWINT)|(1<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC) |
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ISR (TWI_vect) |
{ |
uint8_t data; |
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// check event |
switch (TW_STATUS) |
{ |
149,6 → 147,7 |
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; |
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case TW_SR_DATA_ACK: // data has been received and ack has been returned |
160,31 → 159,21 |
case I2C_CMD_VERSION: |
I2C_TxBuffer = (uint8_t *)&I2C_Version; |
I2C_TxBufferSize = sizeof(I2C_Version); |
I2C_RxBuffer = 0; |
I2C_RxBufferSize = 0; |
break; |
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case I2C_CMD_WRITE_EEPROM: |
I2C_TxBufferSize = 0; |
I2C_RxBuffer = (uint8_t *)&I2C_WriteEEPROM; |
I2C_RxBufferSize = sizeof(I2C_WriteEEPROM); |
break; |
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case I2C_CMD_WRITE_CAL: |
I2C_TxBuffer = 0; |
I2C_TxBufferSize = 0; |
I2C_RxBuffer = (uint8_t *)&I2C_WriteCal; |
I2C_RxBufferSize = sizeof(I2C_WriteCal); |
break; |
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case I2C_CMD_READ_EEPROM: |
I2C_TxBuffer = (uint8_t *)&I2C_ReadEEPROM.Content; |
I2C_TxBufferSize = 2; |
I2C_RxBuffer = (uint8_t *)&I2C_ReadEEPROM; |
I2C_RxBufferSize = 1; |
break; |
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case I2C_CMD_READ_MAG: |
I2C_TxBuffer = (uint8_t *)&I2C_Mag; |
I2C_TxBufferSize = sizeof(I2C_Mag); |
I2C_RxBuffer = 0; |
I2C_RxBufferSize = 0; |
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I2C_Mag.MagX = MagnetX; |
203,7 → 192,7 |
ExternData.Attitude[NICK] = I2C_WriteAttitude.Nick; |
ExternData.Attitude[ROLL] = I2C_WriteAttitude.Roll; |
break; |
default: |
default: // unknown command id |
I2C_RxBuffer = 0; |
I2C_RxBufferSize = 0; |
I2C_TxBuffer = 0; |
211,64 → 200,50 |
break; |
} |
Rx_Idx = 0; // set rx buffer index to start of the buffer |
if(I2C_RxBufferSize > 1) TWCR_ACK; // prepare receiving of next byte and send ACK afterwards |
else TWCR_NACK; // prepare receiving of next byte and send NACK afterwards |
} |
else // Rx_Idx != 0xFF |
{ |
// fill receiver buffer with byte that has been received |
// if buffer exist |
if(I2C_RxBuffer != 0) |
{ // and there is still some free space |
if (Rx_Idx < I2C_RxBufferSize) I2C_RxBuffer[Rx_Idx++] = data; |
// if there is space for more than one byte |
if(Rx_Idx < (I2C_RxBufferSize - 1)) TWCR_ACK; |
// with the next incomming byte the rx buffer is full |
else TWCR_NACK; |
// 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; |
} |
// rx buffer does not exist |
else TWCR_NACK; // prepare receiving of next byte and send NACK afterwards |
// else ignore the data |
} |
TWCR_ACK; |
return; |
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case TW_SR_DATA_NACK: // data has been received and NACK has been returned |
// read the last byte that is expected |
data = TWDR; |
if((I2C_RxBuffer != 0) && (Rx_Idx != 0xFF)) |
{ // and there is still some free space |
if (Rx_Idx < I2C_RxBufferSize) I2C_RxBuffer[Rx_Idx++] = data; |
} |
TWCR_RESET; // switched to the non adressed slave mode |
return; |
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case TW_ST_SLA_ACK: // slave transmitter selected |
// reset position in tx buffer |
// reset index to start of tx buffer |
Tx_Idx = 0; |
case TW_ST_DATA_ACK: // data byte has been transmitted ack has been received |
// put next byte from tx buffer to twi data register |
if(I2C_TxBuffer != 0) |
// if tx bufer exist and there is at least ine byte to transfer |
if((I2C_TxBuffer != 0) && (I2C_TxBufferSize > 1)) |
{ |
if (Tx_Idx < I2C_TxBufferSize) |
{ |
TWDR = I2C_TxBuffer[Tx_Idx++]; |
if(Tx_Idx + 1 < I2C_TxBufferSize) TWCR_ACK; // more than one byte to send |
else TWCR_NACK; // last byte was send NACK should be received |
} |
else |
{ // |
{ // send 0x00 if no tx buffer exist or all bytes of the tx buffer have been transmitted |
TWDR = 0x00; |
TWCR_NACK;// NACK should be received |
} |
TWCR_ACK; |
return; |
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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 // buffer not existent |
{ |
else |
{ // send dummy byte instead |
TWDR = 0x00; |
TWCR_NACK;// NACK should be received |
} |
TWCR_ACK; |
return; |
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case TW_BUS_ERROR: // Bus-Error |
TWCR_CLEARBUS; // free bus reset to nonselected slave |
TWCR_CLEARBUS; // free bus, reset to nonselected slave |
return; |
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case TW_ST_DATA_NACK: // data transmitted, NACK received |