//****************************************************************************
//Initiates a read transfer. Loads global variables. Sends START. ISR handles
//the rest.
//****************************************************************************
void twi_start_rd(uint8_t twi_addr, uint8_t *twi_data, uint8_t byte_cnt){
while(twi_busy()); //wait till TWI rdy for next xfer
twi_bus_addr = (twi_addr | TW_READ); //set twi bus address, mark as read
twi_buf = twi_data; //load pointer to write buffer
twi_msg_size = byte_cnt; //load size of xfer
TWCR = TWCR_START; //initiate START
}
void write_LSM6DS3(uint8_t address, uint8_t value){
uint8_t wr_buf[2];
// Save address to address buffer
wr_buf[0] = address;
wr_buf[1] = value;
// Write value to register address
twi_start_wr(LSM6DS3_WRITE, wr_buf, 2);
// Wait until data is sent
while(twi_busy());
}
void read_LSM6DS3(uint8_t address, uint8_t *rd_buf){
uint8_t addr_buf[1];
// Save address to address buffer
addr_buf[0] = address;
// Write register address of where to read data from
twi_start_wr(LSM6DS3_WRITE, addr_buf, 1);
// Recieve data from register address and store in rd_buf
twi_start_rd(LSM6DS3_READ, rd_buf, 1);
// Wait until data is recieved
while(twi_busy());
}
void twi_start_rx(uint8_t adr, uint8_t *data, uint8_t bytes_to_receive)
{
// Wait for previous transaction to finish
while(twi_busy())
{
;
}
// Copy address; set R/~W bit in SLA+R/W address field
//twi_adr = adr | TW_READ;
twi_adr = ( adr << 1 ) | TW_READ;
// Save pointer to data and number of bytes to receive
twi_data = data;
twi_data_counter = bytes_to_receive;
// Initiate a START condition; Interrupt enabled and flag cleared
TWCR = (1<<TWINT)|(0<<TWEA)|(1<<TWSTA)|(0<<TWSTO)|(0<<TWWC)|(1<<TWEN)|(1<<TWIE);
}
void twi_stop(void)
{
// Wait for transaction to finish
while(twi_busy())
{
;
}
// Make sure transaction was succesful
if(twi_status != TWI_STATUS_DONE)
{
return;
}
// Initiate a STOP condition
TWCR = (1<<TWINT)|(0<<TWEA)|(0<<TWSTA)|(1<<TWSTO)|(0<<TWWC)|(1<<TWEN)|(0<<TWIE);
// Wait until STOP has finished
LOOP_UNTIL_BIT_IS_LO(TWCR, TWSTO);
}
void
ecmd_twi_periodic(void)
{
if (!twi_busy()) //wait until TWI interrupt is disabled
{
TWIDEBUG("ecmd_twi_periodic\n");
cmd_rx_len=twi_rx_len();
if (cmd_rx_len<=2) //assume its raw
parse_rawdata_twi_slave();
else
{
parse_ecmd_twi_slave();
}
TWCR = (1<<TWEN)| // TWI Interface enabled
(1<<TWIE)|(1<<TWINT)| // Enable TWI Interupt and clear the flag to send byte
(1<<TWEA)|(0<<TWSTA)|(0<<TWSTO)| // Send ACK after next reception
(0<<TWWC);
}
}
