Hello Everyone!
MSP430f5438A
tirtos_msp430_2_00_02_36
I have found a bug in I2C Interrupt service routine in CallBack mode.
I2CUSCIB.c
case I2C_READ_MODE:
/*
* Data has been read from RXBUF, but the next byte is
* already been shifted
*/
object->readCountIdx--;
if (object->readCountIdx > 1)
{
*(object->readBufIdx) = USCI_B_I2C_slaveDataGet(hwAttrs->baseAddr);
}
else if (object->readCountIdx == 1)
{
key = Hwi_disable();
*(object->readBufIdx) = USCI_B_I2C_masterMultiByteReceiveFinish(hwAttrs->baseAddr);
Hwi_restore(key);
}
else
{
/* Next state: Idle mode */
object->mode = I2C_IDLE_MODE;
*(object->readBufIdx) = USCI_B_I2C_slaveDataGet(hwAttrs->baseAddr);
I2CUSCIB_completeTransfer((I2C_Handle)&I2C_config[index]);
}
Log_print2(Diags_USER2, "I2C:(%p) ISR I2C_READ_MODE: "
"Read data byte: 0x%x ",
hwAttrs->baseAddr,
*(object->readBufIdx));
object->readBufIdx++;
break; /* I2C_READ_MODE */
So in CallBack mode, I2CUSCIB_completeTransfer() function calls I2CUSCIB_primeTransfer() function that sets the object->readBufIdx. So after returning from the I2CUSCIB_completeTransfer() function, object->readBufIdx++; increments the readBufIdx pointer and the pointer points to the next memory location that saves the data at the new memory location instead of the original location.
This is how I fix it
case I2C_READ_MODE:
/*
* Data has been read from RXBUF, but the next byte is
* already been shifted
*/
object->readCountIdx--;
if (object->readCountIdx > 1)
{
*(object->readBufIdx) = USCI_B_I2C_slaveDataGet(hwAttrs->baseAddr);
object->readBufIdx++;
}
else if (object->readCountIdx == 1)
{
key = Hwi_disable();
*(object->readBufIdx) = USCI_B_I2C_masterMultiByteReceiveFinish(hwAttrs->baseAddr);
Hwi_restore(key);
object->readBufIdx++;
}
else
{
/* Next state: Idle mode */
object->mode = I2C_IDLE_MODE;
*(object->readBufIdx) = USCI_B_I2C_slaveDataGet(hwAttrs->baseAddr);
I2CUSCIB_completeTransfer((I2C_Handle)&I2C_config[index]);
}
Log_print2(Diags_USER2, "I2C:(%p) ISR I2C_READ_MODE: "
"Read data byte: 0x%x ",
hwAttrs->baseAddr,
*(object->readBufIdx));
break; /* I2C_READ_MODE */
Regards
Arslan
