LP-MSPM0G3507: Uart Tx interrupt handling

Here is what I do:

My Interrupt handler for the back channel UART:

void UART_0_INST_IRQHandler(void) {
  switch (DL_UART_Main_getPendingInterrupt(UART_0_INST)) {

  case DL_UART_MAIN_IIDX_RX:
    RXdata = DL_UART_Main_receiveData(UART_0_INST);
    // DL_UART_Main_transmitData(UART_0_INST, RXdata);
    break;

  case DL_UART_MAIN_IIDX_TX:
    if (TXData[TXChar] != '\0') {
      DL_UART_Main_transmitData(UART_0_INST, TXData[TXChar++]);
    } else {
      TXChar = -1;
    }

    break;

  default:
    break;
  }
}

Note the commented code in the RX handler, I just took this directly from the echo example.

Does the Echo Example work for you?

How I kick it off:

void StartSerialTX(char *str) {

  while (TXChar != -1) {
    // wait for previous tx to finish
    Delay(10);
  }

  strcpy(TXData, str);

  TXChar = 0;

  DL_UART_Main_transmitData(UART_0_INST, TXData[TXChar++]);
}

In your code, I don't see how you stop? It seems that it would just keep spinning through memory sending data.

Also, you don't need curly braces inside the switch(). The compiler can figure out the code flow on its own. All it does is suck up another layer of indentation.

Here, How do we stop the transmission, and when does it stop? Is there anything related to the EOT (End of Transmission) interrupt specifically for transmitting data?

I have never used EOT, and you can't use that because it does not now how much data you are sending.

for you it can be as simple as

#define BYTES_TO_SEND (5)

and in your transmit interrupt:

if (index < BYTES_TO_SEND)  // once index gets to 5 it will stop sending

{

  Tx_isr(); // it is better in an interrupt to eliminate extra function calls, just put the code here.

}

Hi,

Here is the demo code that used for sending messages via EOT interrupt.

Touchvsion_UART_TX_interrupt_C.zip

Regards,

Zoey

Is this code is tested. don't we need to enable TXINT only enabling EOT is fine. 

Yes.

This is used for our customer, and they have already tested for that.

Regards,

Zoey

This example is working in ccs, I am doing the same, but EOT interrupt is not coming always so i was not able to send entire buffer data.

Is only enabling EOT interrupt is enough or do we need to enable TXINT also.

Yes, EOT is enough.

Can you find what's situation will cause EOT interrupt not coming? My customers and I have never seen this phenomenon before.

This I found in reference manual, what I understand is that TXINT will set when TXDATA register empty if we are not using FIFO's. I think we should get TXINT also every time after byte sent. 

Now EOT interrupt coming, there is some issue with my interrupt configuration.

#include "ti_msp_dl_config.h"

volatile uint8_t gSendData[6] = {0x00,0x01,0x02,0x03,0x04,0x05};
uint8_t i=0;
int main(void)
{
    NVIC_ClearPendingIRQ(UART_0_INST_INT_IRQN);
    NVIC_EnableIRQ(UART_0_INST_INT_IRQN);

    SYSCFG_DL_init();

    //Start to transmit
    // DL_UART_transmitData(UART_0_INST,gSendData[i++]);
    while (1) {
        __WFI();
    }
}

void UART_0_INST_IRQHandler(void)
{
    switch (DL_UART_Main_getPendingInterrupt(UART_0_INST)) {
        case DL_UART_MAIN_IIDX_TX:
            if(i < 6)
            {
                DL_UART_transmitData(UART_0_INST,gSendData[i++]);
            }
            else
                DL_UART_Main_disableInterrupt(UART_0_INST,DL_UART_MAIN_IIDX_TX);

            break;
        default:
            break;
    }
}

I have tried with TXINT also, we no need to send 1 byte initially if we TXINT instead of EOT. It working now.

TXINT is working now.

I am enabling all error interrupts during uart initialization, I could see frame error and break error first before tx- interrupt comes. what could be the issue?

What error do you want? Have you the wrong error data to check?

These error interrupts i am enabling.

I am getting frame error and break error initially. ideally i should not get.

Ok.

But have you send the wrong data(maybe the data has the break error or frame error?) from another device 

I am not receiving any data from my device, currently i am just sending from my device. during sending i am observing these error s if i enable the errors. 

These error interrupt only happens while receiving error data.

Hi, I am sending 0x55 data 5 times over uart using TXINT. my first byte is corrupting always.

I am getting first byte as 0x56 instead of 0x55. what could be the issue? 

Hi,

There is a low abnormal voltage, and I think this might due to TXINT or hardware disturbance.

Regards,

Zoey

I did not observe this issue when I use code from CCS, Same code I am using in my environment that time I could see this issue, Do you think Any pin configuration(push-pull/open-drain, pullup/pull-down) causes this issue on tx/rx pins?

Which pins do you use and have you used sysconfig? or just maybe you can copy the same file into CCS to check

These pins 

with below configuration.

tx- pushpull, pull-up/pull-down disabled.

rx- pushpull, pull-up/pull-down disabled.

which IDE do you use?

And can you upload your project to let me check?

#include "ti_msp_dl_config.h"

volatile uint8_t gSendData[6] = {0x00,0x01,0x02,0x03,0x04,0x05};
uint8_t i=0;
int main(void)
{
    NVIC_ClearPendingIRQ(UART_0_INST_INT_IRQN);
    NVIC_EnableIRQ(UART_0_INST_INT_IRQN);

    SYSCFG_DL_init();

    //Start to transmit
    // DL_UART_transmitData(UART_0_INST,gSendData[i++]);
    while (1) {
        __WFI();
    }
}

void UART_0_INST_IRQHandler(void)
{
    switch (DL_UART_Main_getPendingInterrupt(UART_0_INST)) {
        case DL_UART_MAIN_IIDX_TX:
            if(i < 6)
            {
                DL_UART_transmitData(UART_0_INST,gSendData[i++]);
            }
            else
                DL_UART_Main_disableInterrupt(UART_0_INST,DL_UART_MAIN_IIDX_TX);

            break;
        default:
            break;
    }
}

Here I can send one frame of data ex: a[] = {1,2,3,4,5} after sending last byte we are disabling the interrupt.

If I want to send next frame of data ex:a[]={1,2,3,4,5} again I am enabling the Tx- interrupt, but second time Tx- interrupt is not occurring.

But when I write first byte UART0->TXDATA=a[0], then after Tx-interrupt is coming and i am able to push remaining data.

Generally, Tx interrupt should come without writing first byte into TXDATA register. This is happening once in power on but after that in run time it is not happening.

Need help with this and when TXINT will occurs and how it works? The information mentioned in reference manual about TXINT is not so clear.

Thanks.

Hi,

As we all not used this interrupt before, I will check from my side and update to you.