C5505 UART interrupt problem

Yiyuan Sun

Hi,

We encounter the following UART interrupt problem:

After power up, the UART is working normally, but after a while, the CPU stops getting UART recieve interrupt anymore. The UART bit in register IER is set, but the bit in IFR is not set. We found that the UART register IIR shows that the recieve interrupt is pending (IPEND bit is set and INTID bits == 2).

Thanks much for any help,

Yiyuan

over 14 years ago

0 Hyun Kim over 14 years ago

TI__Genius 14965 points

Hi Yiyuan,

Which software are you using? How long do you need to wait to see this happens? Does it happen repeatable?

Regards,

Hyun

0 Yiyuan Sun over 14 years ago in reply to Hyun Kim

Intellectual 345 points

We do not use CSL for UART module. Is there other support library for UART?

Usually it will happen within 1 minute and it is repeatable.

Thanks,

Yiyuan

0 Hyun Kim over 14 years ago in reply to Yiyuan Sun

TI__Genius 14965 points

Is there a reason not to use CSL? Can you try with CSL?

Yes, there is PSP URAT driver under development.

Regards,

Hyun

0 Yiyuan Sun over 14 years ago in reply to Hyun Kim

Intellectual 345 points

We have reusable code for the UART, so we are using it now.

I will check CSL for the UART functions.

Thanks,

Yiyuan

0 Yiyuan Sun over 14 years ago in reply to Yiyuan Sun

Intellectual 345 points

More information:

When I disable all other interrupts, the UART is working normally. But if the timer and its interrupt are enabled, the UART will stop working after a while.

Thanks,

Yiyuan

0 Hyun Kim over 14 years ago in reply to Yiyuan Sun

TI__Genius 14965 points

hi Yiyuan,

Sorry for the late response. Are you still use your code or is this from CSL example?

I'll send you my contact info by message. If you need it, you can contact me directly.

Regards,

Hyun

0 Ricardo Zepeda over 14 years ago in reply to Hyun Kim

TI__Prodigy 690 points

Yiyuan,

Hi Yiyuan have you resolved this dilemma? If not, check your “reusable code” and make sure that none of the previous function calls or commands are modifying any of the bits on the UART registers. Try using CSL and see if the problem persists.

0 Yiyuan Sun over 14 years ago in reply to Ricardo Zepeda

Intellectual 345 points

Hi Ricardo,

Thanks for your reply and sorry for the late response, since i have moved to other projects. The following is the message sent to Hyun month ago.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thanks for the information.

Regarding the UART interrupt problem, we are still using our code. But we found that if the IRQ_Clear function is removed from the following timer ISR, the UART problem is just gone.

interrupt void gptIsr(void)
{

Int16 savedIER0, savedIER1;

savedIER0 = *(volatile UInt16 *)IER0;
savedIER1 = *(volatile UInt16 *)IER1;

  if(*(ioport UInt16 *)TIAFR & 0x0001)
     gpt0Isr(); //Clear appropriate timer bit in TIAFR in routine.
  else if(*(ioport UInt16 *)TIAFR & 0x0004)
     wdtimer_isr_C(); //Clear appropriate timer bit in TIAFR in routine.

  //IRQ_clear(TINT_EVENT); // <-- removed
  *(volatile UInt16 *)IER0 |= savedIER0;
  *(volatile UInt16 *)IER1 |= savedIER1;

return;
}

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is more like a question now, since we do not understand why calling IRQ_clear (in red) will influence UART interrupt.

Thanks,

Yiyuan

0 Varun Shah over 14 years ago in reply to Yiyuan Sun

TI__Intellectual 2470 points

Yiyuan,

You are right. It seems that someone else too found issue with IRQ_clear() and made efforts to rectify it. Please check the post: http://e2e.ti.com/support/dsp/tms320c5000_power-efficient_dsps/f/110/t/70685.aspx.

Let me know if this solves the problem.

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C5505 UART interrupt problem