I have downloaded one demo code for i2c communication for MSP430F4152 controller
i have 32.768Khz external crystal and 4.7K pullup resistors are connected to the SDA and SCL line
and i checked signals on pin 1 and 2 but it is not showing any pulses on SCL and SDA
please check the code
int TXByteCtr;
unsigned char PRxData;
int Rx = 0;
char WHO_AM_I = 0x00;
unsigned char itgAddress = 0xA0;
void init_I2C(void);
void Transmit(void);
void Receive(void);
int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P6SEL |= BIT1+BIT2; // Assign I2C pins to USCI_B0
//P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0
//P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0
init_I2C();
while(1)
{
//Transmit process
Rx = 0;
TXByteCtr = 1;
Transmit();
//Receive process
Rx = 1;
Receive();
}
}
//-------------------------------------------------------------------------------
// The USCI_B0 data ISR is used to move received data from the I2C slave
// to the MSP430 memory. It is structured such that it can be used to receive
//-------------------------------------------------------------------------------
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
if(Rx == 1)
{ // Master Recieve?
PRxData = UCB0RXBUF; // Get RX data
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
}
else
{ // Master Transmit
if (TXByteCtr) // Check TX byte counter
{
UCB0TXBUF = WHO_AM_I; // Load TX buffer
TXByteCtr--; // Decrement TX byte counter
}
else
{
UCB0CTL1 |= UCTXSTP; // I2C stop condition
IFG2 &= ~UCB0TXIFG; // Clear USCI_B0 TX int flag
__bic_SR_register_on_exit(CPUOFF); // Exit LPM0
}
}
}
void init_I2C(void) {
UCB0CTL1 |= UCSWRST; // Enable SW reset
UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset
UCB0BR0 = 1; // fSCL = SMCLK/12 = ~100kHz
UCB0BR1 = 0;
UCB0I2CSA = itgAddress; // Slave Address is 069h
UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
IE2 |= UCB0RXIE + UCB0TXIE; //Enable RX and TX interrupt
}
void Transmit(void){
while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent
UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition
__bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts
}
void Receive(void){
while (UCB0CTL1 & UCTXSTP); // Ensure stop condition got sent
UCB0CTL1 &= ~UCTR ; // Clear UCTR
UCB0CTL1 |= UCTXSTT; // I2C start condition
while (UCB0CTL1 & UCTXSTT); // Start condition sent?
UCB0CTL1 |= UCTXSTP; // I2C stop condition
__bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts
}
Please guide us as our R & D and further production is struct up
Regards,
Anushka
