MSP430FR2355: I2C master

Hi,
Can you post the wave using oscilloscope?
Have you use a pull up resistor?
Eason

Hi Eason,

scope shows 3.3V, straight line on both signals SDA and SCL

both signals have 10k pull up

best regards
Kurt

Hi,
Have you make a compare with our sample code?
If you still can't solve it, please post your code.
Eason

Hi Eason,

very strange, I used an old version HW with the same software and it works.


here is the init code for the module

void Init_MASTER(void){
MasterMode = MASTER_IDLE;
UCB1CTLW0 = UCSWRST; // put eUSCI_B in reset state
UCB1CTLW0 |= UCMODE_3 + +UCSYNC + UCMST + UCSSEL1 + UCSSEL0; // I2C master mode
UCB1BRW = 0x5A; // 0x5A pulse width H or L >4.7us!
UCB1CTLW0 &= ~UCSWRST; // eUSCI_B in operational state
UCB1IE |= UCNACKIE;
}


here is the TX code

void I2C_Master_ReadReg(unsigned char dev_addr, \
unsigned char reg_addr, \
unsigned char count,
unsigned char *pData, \
I2C_Callback Sub){
while(!(MasterMode == MASTER_IDLE)); //Wait till I2C ready
MasterMode = TX_REG_ADDRESS_MODE; // Initialize state machine
MasterTransmitRegAddr = reg_addr; // Register address to start to read from
MasterRXByteCtr = count; // How many Bytes to read
pMasterRXDATA = pData; // Set pointer to receive buffer
RXFunc = Sub; // Function to run after bytes received
UCB1I2CSA = dev_addr; // Set slave address
MasterTXByteCtr = 0;
UCB1IFG &= ~(UCTXIFG + UCRXIFG); // Clear any pending interrupts
UCB1IE &= ~UCRXIE; // Disable RX interrupt
UCB1IE |= UCTXIE; // Enable TX interrupt
UCB1CTLW0 |= UCTR + UCTXSTT; // I2C TX, start condition
}



on the new PCB the UCBBUSY in the UCB1STATW register is set as soon as UCSWRT goes low. I assume when the UCBBUSY BIT is high you can't send any start/stop or bytes?

on the old PCB the UCBBUSY goes only high after the UCB1CTLW0 |= UCTR + UCTXSTT line

I assume there is something wrong with the chip???? = brand new out of the box! I hand soldered it, maybe tooo hot?

thanks for your help
Kurt

Eason,

resoldering the slave and replacing the MSP430 fixed the problem.

bets regards
Kurt