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TMS320F280039C: TMS320F280039C SPI Master configuration.

Rahul Jathar
Prodigy 150 points
Part Number: TMS320F280039C
Other Parts Discussed in Thread: SYSCONFIG

Hi All,

i am interfacing two  TMS320F280039C launchpad boards. one as master & another as slave.

i need master configuration 1 byte receive interrupt . no loopback , 500Kbps.

this is my current configuration generated from sysconfig tool: 

void SPIA_MASTER_init()

{
SPI_disableModule(SPIA_MASTER_BASE);
SPI_setConfig(SPIA_MASTER_BASE, DEVICE_LSPCLK_FREQ, SPI_PROT_POL0PHA0,
SPI_MODE_MASTER, 500000, 8);
SPI_disableFIFO(SPIA_MASTER_BASE);
SPI_clearInterruptStatus(SPIA_MASTER_BASE, SPI_INT_RX_DATA_TX_EMPTY);
SPI_enableInterrupt(SPIA_MASTER_BASE, SPI_INT_RX_DATA_TX_EMPTY);
SPI_disableLoopback(SPIA_MASTER_BASE);
SPI_setEmulationMode(SPIA_MASTER_BASE, SPI_EMULATION_FREE_RUN);
SPI_enableModule(SPIA_MASTER_BASE);
}

  • 0
    TI__Guru 55700 points

    Rahul,

    (1) 8 represent datawidth - The dataWidth parameter defines the width of the data transfers and can be a value between 1 and 16, inclusive.

            In your cause you are configuring SPI to have byte by byte transaction.

    (2) SPI_INT_RX_DATA_TX_EMPTY - When you choose this option SPI interrupt is generated by a data received (or) when transmit operation is complete

    (3) SPI_setEmulationMode(SPIA_MASTER_BASE, SPI_EMULATION_FREE_RUN); - You can configure SPI to stop transaction on a debugger halt. In your case, you have configured SPI not to stop SPI transaction on debugger halt. No issues with this configuration.

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Prodigy 150 points

    Hi Manoj , Thanks for the information. 

    one more question : My Master Receive interrupt is trigger if i call SPI_writeDataBlockingNonFIFO(SPIA_BASE,TxData_u16[i] );. i get same data in receive interrupt which i am transmitting Rx_byte = SPI_readDataNonBlocking(SPIA_BASE);

    Is there any API in TMS320F280039C to get Master receive interrupt only if actual slave data received?

  • 0 in reply to Rahul Jathar
    TI__Guru 55700 points

    Rahul,

    Just to be clear. Here is my understand of what you are trying to do

    Board1.SPIA is Controller (Master)

    Board2.SPIA is Peripheral (Slave)

    Rahul Jathar said:
    one more question : My Master Receive interrupt is trigger if i call SPI_writeDataBlockingNonFIFO(SPIA_BASE,TxData_u16[i] );. i get same data in receive interrupt which i am transmitting Rx_byte = SPI_readDataNonBlocking(SPIA_BASE);

    Board1.SPIA initiates are transaction when you execute "SPI_writeDataNonBlocking(SPIA_BASE, 1 byte data to be transmitted to Board2.SPIA);". This should transmit 1 byte of data to Board2.SPIA generating an SPI interrupt on Board2. SPIA. In board2.SPIA ISR, you read the contents in SPI RX buffer (read contents should be what board1.SPIA transmitted), then board2.SPI can execute SPI_writeDataNonBlocking(SPIA_BASE, 1 byte data to be transmitted to Board1.SPIA). This should trigger SPI interrupt on Board1.SPIA where you can read what board2.SPIA transmitted.

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Prodigy 150 points

    hi Manoj,

    you above observation is right. 2 boards Master & slave  using SPIA.

    but Master is  getting same data in receive interrupt which Master is transmitting. but master should only get receive interrupt only if slave is transmitting data. 

  • 0 in reply to Rahul Jathar
    TI__Guru 55700 points

    Rahul,

    If your peripheral (slave) SPI isn't ready with data to be transmitted, then peripheral (slave) SPI is re-transmit what it received. To avoid that, make sure SPI slave has the data to be transmitted in SPITXBUF before master SPI initializes transaction.

    Regards,

    Manoj

  • 0 in reply to Manoj Santha Mohan
    Prodigy 150 points

    hi manoj ,

    below are my requirement :

    1. SPIA as master.

    2. Baud rate : 500kbps

    3. Receive interrupt 1 byte (do not want transmit interrupt).

    4. SPI Mode 0: Polarity 0 Phase 0.

    Please check below configuration & let me know where i should modify.

  • 0 in reply to Rahul Jathar
    TI__Guru 55700 points

    Above configuration does look right for what you are trying to do.

    Regards,

    Manoj

  • +1 in reply to Manoj Santha Mohan
    TI__Guru 55700 points

    Root cause of customer problem: BQ79731 SPI mode 0 strobes for data on rising edge and changes data on falling edge. But customer was operating SPI master in strobe for data on falling edge and changes data on rising edge. Customer was confused because SPI mode 0 specified in BQ79731 was different from F280039 SPI mode 0. If customer had taken a closer look into timing diagram in both the datasheet, this problem could have been avoided

  • +1 in reply to Manoj Santha Mohan
    Prodigy 150 points

    Thank you Manoj,

    My issue is resolved.

  • 0 in reply to Rahul Jathar
    TI__Guru 55700 points

    Closing this thread