inline int i2c_start(i2c_t *obj) {
int status = 0;
int isInterrupted = I2C_CONSET(obj) & (1 << 3);
// 8.1 Before master mode can be entered, I2CON must be initialised to:
// - I2EN STA STO SI AA - -
// - 1 0 0 x x - -
// if AA = 0, it can't enter slave mode
i2c_conclr(obj, 1, 1, 0, 1);
// The master mode may now be entered by setting the STA bit
// this will generate a start condition when the bus becomes free
i2c_conset(obj, 1, 0, 0, 1);
// Clearing SI bit when it wasn't set on entry can jump past state
// 0x10 or 0x08 and erroneously send uninitialized slave address.
if (isInterrupted)
i2c_clear_SI(obj);
i2c_wait_SI(obj);
status = i2c_status(obj);
// Clear start bit now that it's transmitted
i2c_conclr(obj, 1, 0, 0, 0);
return status;
}
void i2c_slave_mode(i2c_t *obj, int enable_slave) {
if (enable_slave != 0) {
i2c_conclr(obj, 1, 1, 1, 0);
i2c_conset(obj, 0, 0, 0, 1);
} else {
i2c_conclr(obj, 1, 1, 1, 1);
}
}
inline void i2c_stop(i2c_t *obj) {
// write the stop bit
i2c_conset(obj, 0, 1, 0, 0);
i2c_clear_SI(obj);
// wait for STO bit to reset
while(I2C_CONSET(obj) & (1 << 4));
}
inline int i2c_stop(i2c_t *obj) {
int timeout = 0;
// write the stop bit
i2c_conset(obj, 0, 1, 0, 0);
i2c_clear_SI(obj);
// wait for STO bit to reset
while(I2C_CONSET(obj) & (1 << 4)) {
timeout ++;
if (timeout > 100000) return 1;
}
return 0;
}
static inline int i2c_do_read(i2c_t *obj, int last) {
// we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack)
if(last) {
i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK
} else {
i2c_conset(obj, 0, 0, 0, 1); // send a ACK
}
// accept byte
i2c_clear_SI(obj);
// wait for it to arrive
i2c_wait_SI(obj);
// return the data
return (I2C_DAT(obj) & 0xFF);
}
inline int i2c_start(i2c_t *obj) {
int status = 0;
// 8.1 Before master mode can be entered, I2CON must be initialised to:
// - I2EN STA STO SI AA - -
// - 1 0 0 0 x - -
// if AA = 0, it can't enter slave mode
i2c_conclr(obj, 1, 1, 1, 1);
// The master mode may now be entered by setting the STA bit
// this will generate a start condition when the bus becomes free
i2c_conset(obj, 1, 0, 0, 1);
i2c_wait_SI(obj);
status = i2c_status(obj);
// Clear start bit now transmitted, and interrupt bit
i2c_conclr(obj, 1, 0, 0, 0);
return status;
}
