TMS320F28035: I2CFFTX register TXFFINT bit is not clear

Deepak Omanna

Part Number: TMS320F28035

HI !

After power on reset i am initializing the I2C device. Here i observed that TXFFINT is set to 1. As i am making Transmit FIFO interrupt TXFFINTCLR = 1 before and after assigning data to I2CFFTX register. But the TXFFINT is not set to 0.

Any suggestion to make TXFFINT = 0.

Please refer the attached file.

over 8 years ago

0 Kevin Allen18 over 8 years ago

TI__Mastermind 45606 points

Hi Deepak,

Have you checked if the TXFFST register is less than the TXFFIL register? The interrupt flag will be triggered if TXFFST < TXFFIL.

You can also refer to these two previous posts for help:

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/38350

https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/94221

Hope this helps,

Kevin

0 Deepak Omanna over 8 years ago in reply to Kevin Allen18

Prodigy 145 points

I agree that when TXFFST4-0 == TXFFIL4-0 interrupt flag is set.

But in the data sheet it mentioned that,

To avoid any detrimental effects from this, write a one to the TXFFINTCLR once the transmit FIFO operation is enabled.

So i am making TXFFINTCLR = 1 once the register I2CFFTX is configured or transmit FIFO operation is enabled.

Then also TXFFINT is not cleared.

0 Manoj Santha Mohan over 8 years ago in reply to Deepak Omanna

TI__Guru 55700 points

Deepak,

TXFFINT flag bit gets set when TXFFST <= TXFFIL.

Now, when you bring I2C FIFO out of reset, both TXFFST and TXFFIL are set to 0. Since, it satisfies the above condition TXFFINT flag bit gets set. TXFFINT flag bit cannot be cleared unless TXFFST > TXFFIL. If you want to clear this flag, try filling your TXFIFO buffer (This will make TXFFST > 0) and then try clearing this flag bit.

Regards,
Manoj

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TMS320F28035: I2CFFTX register TXFFINT bit is not clear