unsigned char EEPROM_RandomRead(unsigned int Address)
// Description:
// Random Read Operation. Data is read from the EEPROM. The EEPROM
// address is defined with the parameter Address.
{
unsigned char adr_hi;
unsigned char adr_lo;
while (I2CDCTL&I2CBB); //http://www.ti.com/lit/er/slaz018d/slaz018d.pdf
adr_hi = Address >> 8; // calculate high byte
adr_lo = Address & 0xFF; // and low byte of address
I2CBuffer[1] = adr_hi; // store single bytes that have to be sent
I2CBuffer[0] = adr_lo; // in the I2CBuffer.
PtrTransmit = 1; // set I2CBuffer Pointer
I2CWriteInit();
I2CNDAT = 2; // 1 control byte + 2 bytes should be transmitted
I2CIFG &= ~ARDYIFG; // clear Access ready interrupt flag
I2CTCTL |= I2CSTT; // start condition generation
// => I2C communication is started
while ((~I2CIFG)&ARDYIFG); // wait untill transmission is finished
I2CReadInit();
I2CNDAT = 1; // 1 byte should be received
PtrReceive = 0;
I2CIFG &= ~ARDYIFG; // clear Access ready interrupt flag
I2CTCTL |= I2CSTT+I2CSTP; // start receiving and finally generate
// re-start and stop condition
while ((~I2CIFG)&ARDYIFG); // wait untill transmission is finished
return I2CBuffer[0];
}
void readFromAddress(uint8_t address , unsigned char * Data , unsigned int Size)
{
uint8_t addressWord = address;
counterSize = Size;
while(UCB0STAT & UCBUSY);
I2CWriteInit();
UCB0CTL1 |= UCTXSTT;
while(UCB0CTL1 & UCTXSTT) {
if(!(UCNACKIFG & UCB0STAT));
break;
}
UCB0TXBUF = addressWord;// Load TX buffer
if(UCB0STAT & UCNACKIFG) // nack received this should not happen if address is correct
{
UCB0STAT &= ~UCNACKIFG;
UCB0CTL1 |= UCTXSTP; //stop...
while(UCB0CTL1 & UCTXSTP);
return; //... and exit
}
while(!(UCB0TXIFG & IFG2));
// Read Data byte
I2CReadInit();
UCB0CTL1 |= UCTXSTT; // I2C start condition
while(UCB0CTL1 & UCTXSTT) // Start condition sent?
{
if(!(UCNACKIFG & UCB0STAT)) // Break out if ACK received
break;
}
if(UCB0STAT & UCNACKIFG) // nack received this should not happen if address is correct
{
UCB0STAT &= ~UCNACKIFG;
UCB0CTL1 |= UCTXSTP; //stop...
while(UCB0CTL1 & UCTXSTP);
return;
}
}
/*---------------------------------------------------------------------------*/
unsigned char EEPROM_CurrentAddressRead(void)
// Description:
// Current Address Read Operation. Data is read from the EEPROM. The current
// address from the EEPROM is used.
{
// while (I2CDCTL&I2CBUSY); // wait until I2C module has finished all operations
while (I2CDCTL&I2CBB); //http://www.ti.com/lit/er/slaz018d/slaz018d.pdf
I2CReadInit();
U0CTL |= MST; // define Master Mode
I2CNDAT = 1; // 1 byte should be received
I2CIFG &= ~ARDYIFG; // clear Access ready interrupt flag
I2CTCTL |= I2CSTT+I2CSTP; // start receiving and finally generate
// re-start and stop condition
while ((~I2CIFG)&ARDYIFG); // wait untill transmission is finished
return I2CBuffer[0];
}
int main(void)
{
unsigned int j;
WDTCTL = WDTPW | WDTHOLD; // Stop WDT
if (CALBC1_8MHZ==0xFF) // If calibration constant erased
{
while(1); // do not load, trap CPU!!
}
DCOCTL = 0; // Select lowest DCOx and MODx settings
BCSCTL1 = CALBC1_8MHZ; // Set DCO to 8MHz. This is needed for SCL = 400 KHz
DCOCTL = CALDCO_8MHZ;
P3SEL |= 0x06; // Assign I2C pins to USCI_B0
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMST | UCMODE_3 | UCSYNC; // I2C Master, synchronous mode
UCB0CTL1 = UCSSEL_2 | UCSWRST; // Use SMCLK, keep SW reset
UCB0BR0 = 18; // fSCL = SMCLK/18 = ~400kHz
UCB0BR1 = 0;
UCB0I2CSA = 0x48; // Slave Address is 048h
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
while(1)
{
/*---------------------------------------------------------------------------*/
// Start communication with write operation. Send a start with address and
// send NUM_BYTES_TX bytes.
/*---------------------------------------------------------------------------*/
while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent
I2CWriteInit(); // Init I2C module for a write operation
UCB0CTL1 |= UCTXSTT; // start condition generation
__delay_cycles(400); // Delay. This is needed when running at 400 KHz
for(j = 0; j < NUM_BYTES_TX; j++) // send NUM_BYTES_TX bytes.
{
if(UCB0TXIFG & IFG2)
{
UCB0TXBUF = MSData++; // Load TX buffer
IFG2 &= ~UCB0TXIFG; // Clear USCI_B0 TX interrupt flag
while (UCB0STAT & UCBUSY); // wait until I2C module serve for this transmit,arbitration is not lost
// __delay_cycles(150); // Delay between two bytes
}
}
/*---------------------------------------------------------------------------*/
// Send a RESTART condition with a Read operation. Send start with address and
// read NUM_BYTES_RX bytes.
/*---------------------------------------------------------------------------*/
PRxData = (unsigned char *)RxBuffer; // Start of RX buffer
counter=0;
I2CReadInit(); // Init I2C module for a read operation
UCB0CTL1 |= UCTXSTT; // start condition generation
while(UCB0CTL1 & UCTXSTT); // Start condition sent?
__bis_SR_register(LPM0_bits | GIE); // Enter LPM0 w/ interrupts. Stay in LPM until all expected bytes are read
while(UCB0CTL1 & UCTXSTP); // Stop condition sent?
__delay_cycles(50); // Delay between STOP and new START condition
}
}
