Hi all,

I'm having trouble getting the USCIB0 module to work as an I2C master in
my 2619 device.
I have followed the code for application note "slaa382" (I have tried
both with and without DMA) but I can't get any I2C-traffic on the bus.

When using an oscilloscope I see that the SCL line stays high and SDA
line stays low after I reset the board.

The configuration code for the USCIB0 looks like:

void I2C_Init (void)
{
UCB0CTL1 = UCSWRST; // Hold USCIB0 in reset

UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
UCB0CTL1 = UCSSEL_1 + UCSWRST; // Use ACLK
UCB0BR0 = SCL_FREQ_DIV & 0xFF; // Set SCL-freq (150 kHz)
UCB0BR1 = (SCL_FREQ_DIV >> 8); //

P3SEL |= 0x06; // Configure pins

UCB0CTL1 &= ~UCSWRST; // Clear UCSWRST

UCB0I2CIE = UCNACKIE; // Enable I2C state change interrupts
IE2 |= UCB0TXIE; // Enable I2C Tx interrupt
}

Before calling the init function I call __enable_interrupt();

The function to send data looks like:

void I2C_send (uint8_t *data, uint8_t byteCount)
{
volatile uint16_t ii;
while (UCB0STAT & UCBBUSY) { // Wait for I2C-bus to be free
for (ii=0;ii<60000;ii++);
RED_LED_TOGGLE();
}

UCB0I2CSA = 0x0C; // Set slave address

I2C_TransmitData = data;
I2C_TxByteCtr = byteCount;

UCB0CTL1 |= UCTR + UCTXSTT; // I2C Tx, start condition
}

The send function gets stuck in the while-loop.

The ISR looks like:

#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
if (I2C_TxByteCtr == 0){
UCB0CTL1 |= UCTXSTP; // I2C stop condition
IFG2 &= ~UCB0TXIFG; // Clear USCI_B0 TX int flag
}
else {
UCB0TXBUF = *I2C_TransmitData;
I2C_TransmitData++;
I2C_TxByteCtr--;
}
}

Anyone who sees where I go wrong?

Thanks in advance,
Anders

[Non-text portions of this message have been removed]
------------------------------------



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Hello,
I'm in the same exact situation. Did you resolve your issue? If you
did, do you mind sharing?
Thanks!

--- In m...@yahoogroups.com, "andersryl" wrote:
>
> Hi all,
>
> I'm having trouble getting the USCIB0 module to work as an I2C master in
> my 2619 device.
> I have followed the code for application note "slaa382" (I have tried
> both with and without DMA) but I can't get any I2C-traffic on the bus.
>
> When using an oscilloscope I see that the SCL line stays high and SDA
> line stays low after I reset the board.
>
> The configuration code for the USCIB0 looks like:
>
> void I2C_Init (void)
> {
> UCB0CTL1 = UCSWRST; // Hold USCIB0 in reset
>
> UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous
mode
> UCB0CTL1 = UCSSEL_1 + UCSWRST; // Use ACLK
> UCB0BR0 = SCL_FREQ_DIV & 0xFF; // Set SCL-freq (150 kHz)
> UCB0BR1 = (SCL_FREQ_DIV >> 8); //
>
> P3SEL |= 0x06; // Configure pins
>
> UCB0CTL1 &= ~UCSWRST; // Clear UCSWRST
>
> UCB0I2CIE = UCNACKIE; // Enable I2C state change interrupts
> IE2 |= UCB0TXIE; // Enable I2C Tx interrupt
> }
>
> Before calling the init function I call __enable_interrupt();
>
> The function to send data looks like:
>
> void I2C_send (uint8_t *data, uint8_t byteCount)
> {
> volatile uint16_t ii;
> while (UCB0STAT & UCBBUSY) { // Wait for I2C-bus to be free
> for (ii=0;ii<60000;ii++);
> RED_LED_TOGGLE();
> }
>
> UCB0I2CSA = 0x0C; // Set slave address
>
> I2C_TransmitData = data;
> I2C_TxByteCtr = byteCount;
>
> UCB0CTL1 |= UCTR + UCTXSTT; // I2C Tx, start condition
> }
>
> The send function gets stuck in the while-loop.
>
> The ISR looks like:
>
> #pragma vector = USCIAB0TX_VECTOR
> __interrupt void USCIAB0TX_ISR(void)
> {
> if (I2C_TxByteCtr == 0){
> UCB0CTL1 |= UCTXSTP; // I2C stop condition
> IFG2 &= ~UCB0TXIFG; // Clear USCI_B0 TX int flag
> }
> else {
> UCB0TXBUF = *I2C_TransmitData;
> I2C_TransmitData++;
> I2C_TxByteCtr--;
> }
> }
>
> Anyone who sees where I go wrong?
>
> Thanks in advance,
> Anders
>
> [Non-text portions of this message have been removed]
>

------------------------------------



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