TMS320F28379D: SCI UART communication issues

Hello Radha,

Thanks for your question!

The reason for this is actually C-related. To fix this, you will need to change "i<2" to be "i<=2".

The reason is that with your current code, when the loop gets to "2", it will fail the test (because 2 is not less than 2).

Let me know if that fixes the issue!

Regards,

Vince

Hello Vince,

Sorry my bad that should be 3. And if 3 in the code as well. 

I am trying to send a three messages during every ISR at 30 kHz and I still end up missing one. I get a limit of 2 always and I am not able to send more than 2 at any point. The transfer time for all the messages is 3.4 us. Is this something related to the FIFO initialization ?

Thanks & Regards,

Radha

Hi Radha,

This can definitely be caused by the FIFO initialization. If your "xmit" function does not wait for the transmit to complete, then you can end up requesting a transmit while the previous transmit occurs. Would you be able to try a blocking version of your xmit function, similar to this function from C2000Ware:

//*****************************************************************************
//
//! Waits to send a character from the specified port.
//!
//! \param base is the base address of the SCI port.
//! \param data is the character to be transmitted.
//!
//! Sends the character \e data to the transmit buffer for the specified port.
//! If there is no space available in the transmit buffer, or the transmit
//! FIFO if it is enabled, this function waits until there is space available
//! before returning. \e data is a uint16_t but only 8 bits are written to the
//! SCI port.  SCI only transmits 8 bit characters.
//!
//! \return None.
//
//*****************************************************************************
static inline void
SCI_writeCharBlockingNonFIFO(uint32_t base, uint16_t data)
{
    //
    // Check the arguments.
    //
    ASSERT(SCI_isBaseValid(base));

    //
    // Wait until space is available in the transmit buffer.
    //
    while(!SCI_isSpaceAvailableNonFIFO(base))
    {
    }

    //
    // Send a char.
    //
    HWREGH(base + SCI_O_TXBUF) = data;
}

This should avoid any collisions.

If you are able to, implementing the FIFO may also help with this situation, as you can load more data into the buffer.

Regards,

Vince

Hello Vince,

Thank you so much for your reply. I will check this blocking function and get back to you early next week. 

Thanks & Regards,

Radha