TMS320F28377D: SCI communication between two 77D microcontrollers

David,

     I don't know of anything related to the module itself, or the hardware, that would be causing the device to send repeat messages. I expect this to be related to application code.

1. Have you connected the grounds between the devices?
2. Are you seeing any RX errors?

Regards,

Cody

1. Yes, the two devices are grounded together.

2. No, I have not received any RX errors that I have notices...I check before taking the data from the buffer in the RX interrupt.

Here is the sci_init and ISRs

//
// sciaTxFifoIsr - SCIA Transmit FIFO ISR
//
interrupt void sciaTxFifoIsr(void)
{
unsigned int i = 0;

for(; i<4; i++)
{
SciaRegs.SCITXBUF.all=ADCdata[i]; // Send data
}

TXRDY_flag = 0;

PieCtrlRegs.PIEIER9.bit.INTx1 = 1; // PIE Group 9, INT1 - RX INT

SciaRegs.SCIFFTX.bit.TXFFINTCLR=1; // Clear SCI Interrupt flag
// SciaRegs.SCICTL2.bit.TXINTENA = 0; // Disable TX Interrupt
PieCtrlRegs.PIEIER9.bit.INTx2 = 0; // PIE Group 9, INT2
PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ACK
}

//
// sciaRxFifoIsr - SCIA Receive FIFO ISR
//
interrupt void sciaRxFifoIsr(void)
{
unsigned int i = 0;
static unsigned int cnt = 0;

if(SciaRegs.SCIRXBUF.bit.SCIFFFE || SciaRegs.SCIRXBUF.bit.SCIFFPE)
{
//error handling here
i = 6; //to bypass frame read, put a breakpoint here as well for debugging
}

for(; i<2;i++)
{
rdataA[i] = SciaRegs.SCIRXBUF.bit.SAR; //read entire frame - TRY CHANGING THIS TO THE EXAMPLE METHOD
}
RXRCV_flag = 1; //set flag to indicate frame ready
cnt++;

SciaRegs.SCIFFRX.bit.RXFFOVRCLR=1; // Clear Overflow flag
SciaRegs.SCIFFRX.bit.RXFFINTCLR=1; // Clear Interrupt flag

PieCtrlRegs.PIEACK.all|=0x100; // Issue PIE ack
}

//
// scia_fifo_init - Configure SCIA FIFO
//
void scia_fifo_init()
{
SciaRegs.SCICCR.all = 0x0007; // 1 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
SciaRegs.SCICTL1.all = 0x0003; // enable TX, RX, internal SCICLK,
// Disable RX ERR, SLEEP, TXWAKE
SciaRegs.SCICTL2.bit.TXINTENA = 1;
SciaRegs.SCICTL2.bit.RXBKINTENA = 1;
SciaRegs.SCIHBAUD.all = 0x0000;
SciaRegs.SCILBAUD.all = SCI_PRD;
SciaRegs.SCIFFTX.all = 0xC022;
SciaRegs.SCIFFRX.bit.RXFIFORESET = 0; //rst fifo
SciaRegs.SCIFFRX.all = 0x0021;
SciaRegs.SCIFFRX.bit.RXFFIL = 1;
SciaRegs.SCIFFCT.all = 0x00;

SciaRegs.SCICTL1.all = 0x0023; // Relinquish SCI from Reset
SciaRegs.SCIFFTX.bit.TXFIFORESET = 1;
SciaRegs.SCIFFRX.bit.RXFIFORESET = 1;
}

//
// End of file
//

David,

how have you verified the baud rate? Some good ways are:

• Check XCLKOUT
• Read the baud registers at run time
• Measure the Bit times using an oscilloscope

Could you observe the Tx of each device using an oscilloscope, by looking at this output you should be able to determine if the problem is on the Tx side or the Rx side.

Regards,
Cody

I'll give that a try.

I was looking over the documentation for the SCI peripheral and in the idle-line portion it refers to a CPU device address, can you tell me how to find that for the 77D's.  

I'm wondering If the issue is that I am not giving an address in the first byte.

David,

what you are referring to is only for the multi-processor mode of the SCI module.

 Are you planning on using point-to-point communication or a multi-processor communication?

Regards,
Cody