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start updating i2c for timeouts
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@jackhumbert
jackhumbert committed Jun 20, 2018
1 parent bad56a4 commit 76e0d23
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Showing 2 changed files with 46 additions and 71 deletions.
102 changes: 36 additions & 66 deletions drivers/avr/i2c_master.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,24 +19,19 @@ void i2c_init(void)
//TWBR = 10;
}

uint8_t i2c_start(uint8_t address)
i2c_status_t i2c_start(uint8_t address, uint8_t timeout)
{
// reset TWI control register
TWCR = 0;
// transmit START condition
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);

#ifdef I2C_TIMEOUT
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if (timeout && (timer_read() - timeout_timer) > timeout) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while( !(TWCR & (1<<TWINT)) );
#endif
}

// check if the start condition was successfully transmitted
if(((TW_STATUS & 0xF8) != TW_START) && ((TW_STATUS & 0xF8) != TW_REP_START)){ return 1; }
Expand All @@ -46,17 +41,12 @@ uint8_t i2c_start(uint8_t address)
// start transmission of address
TWCR = (1<<TWINT) | (1<<TWEN);

#ifdef I2C_TIMEOUT
timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if (timeout && (timer_read() - timeout_timer) > I2C_TIMEOUT) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while( !(TWCR & (1<<TWINT)) );
#endif
}

// check if the device has acknowledged the READ / WRITE mode
uint8_t twst = TW_STATUS & 0xF8;
Expand All @@ -65,75 +55,60 @@ uint8_t i2c_start(uint8_t address)
return 0;
}

uint8_t i2c_write(uint8_t data)
i2c_status_t i2c_write(uint8_t data, uint8_t timeout)
{
// load data into data register
TWDR = data;
// start transmission of data
TWCR = (1<<TWINT) | (1<<TWEN);

#ifdef I2C_TIMEOUT
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if (timeout && (timer_read() - timeout_timer) > I2C_TIMEOUT) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while( !(TWCR & (1<<TWINT)) );
#endif
}

if( (TW_STATUS & 0xF8) != TW_MT_DATA_ACK ){ return 1; }

return 0;
}

uint8_t i2c_read_ack(void)
i2c_status_t i2c_read_ack(uint8_t timeout)
{

// start TWI module and acknowledge data after reception
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);

#ifdef I2C_TIMEOUT
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if (timeout && (timer_read() - timeout_timer) > I2C_TIMEOUT) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while( !(TWCR & (1<<TWINT)) );
#endif
}

// return received data from TWDR
return TWDR;
}

uint8_t i2c_read_nack(void)
i2c_status_t i2c_read_nack(uint8_t timeout)
{

// start receiving without acknowledging reception
TWCR = (1<<TWINT) | (1<<TWEN);

#ifdef I2C_TIMEOUT
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
uint16_t timeout_timer = timer_read();
while( !(TWCR & (1<<TWINT)) ) {
if (timeout && (timer_read() - timeout_timer) > I2C_TIMEOUT) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while( !(TWCR & (1<<TWINT)) );
#endif
}

// return received data from TWDR
return TWDR;
}

uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length)
i2c_status_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length)
{
if (i2c_start(address | I2C_WRITE)) return 1;

Expand Down Expand Up @@ -197,22 +172,17 @@ uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t le
return 0;
}

uint8_t i2c_stop(void)
i2c_status_t i2c_stop(uint8_t timeout)
{
// transmit STOP condition
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);

#ifdef I2C_TIMEOUT
uint16_t timeout_timer = timer_read();
while(TWCR & (1<<TWSTO)) {
if ((timer_read() - timeout_timer) > I2C_TIMEOUT) {
return 2; // should make these codes standard
}
uint16_t timeout_timer = timer_read();
while(TWCR & (1<<TWSTO)) {
if (timeout && (timer_read() - timeout_timer) > I2C_TIMEOUT) {
return I2C_STATUS_TIMEOUT;
}
#else
// wait for end of transmission
while(TWCR & (1<<TWSTO));
#endif
}

return 0;
}
15 changes: 10 additions & 5 deletions drivers/avr/i2c_master.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,15 +8,20 @@
#define I2C_READ 0x01
#define I2C_WRITE 0x00

typedef i2c_status_t int16_t
#define I2C_STATUS_TIMEOUT (-1)

#define I2C_NO_TIMEOUT 0

void i2c_init(void);
uint8_t i2c_start(uint8_t address);
uint8_t i2c_write(uint8_t data);
uint8_t i2c_read_ack(void);
uint8_t i2c_read_nack(void);
i2c_status_t i2c_start(uint8_t address, uint8_t timeout);
i2c_status_t i2c_write(uint8_t data, uint8_t timeout);
i2c_status_t i2c_read_ack(uint8_t timeout);
i2c_status_t i2c_read_nack(uint8_t timeout);
uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length);
uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length);
uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length);
uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length);
uint8_t i2c_stop(void);
i2c_status_t i2c_stop(uint8_t timeout);

#endif // I2C_MASTER_H

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