ISR not getting invoked

Gowtham Raj

Other Parts Discussed in Thread: TMS320C6748

Hi,

Iam using Code Composer Studio Version: 4.1.3.00038 IDE and tms320c6748 DSP for my design.Iam using UART module and configuring it to work in interrupt mode,the problem is whenever an interrupt occurs the ISR is not invoked.I could see the processor's hardware registers IER(Interrupt enable register) getting enabled and even IFR bit is set via register watch in debug mode.Also the data arrives in the receive buffer and IIR flag for the receive interrupt is set in the UART module.

The IER resisters are successfully enabled and the IFR register is set for the respective interrupt when the data arrives in the receive buffer,but the ISR is not invoked.

could some one help me out in this problem

over 14 years ago

0 Gowtham Raj over 14 years ago

Prodigy 60 points

And one more point to add,i am configuring the UART ISR in .tcf file for hardware number 4.

0 Brad Griffis over 14 years ago in reply to Gowtham Raj

TI__Guru*** 125430 points

Please see this article for instructions on setting up intrerrupts under DSP/BIOS:

http://processors.wiki.ti.com/index.php/Setting_up_interrupts_in_DSP_BIOS

Also, see Table 5-6 "C6748 DSP Interrupts" in the data sheet for the correct number to add in the tcf. For example, for UART0 the number is 38.

0 Gowtham Raj over 14 years ago in reply to Brad Griffis

Prodigy 60 points

Hi Brad,

I Had actually followed up the above link to setup interrupts,but still i face the problem and if u want i can even share the code.

0 RandyP over 14 years ago in reply to Gowtham Raj

TI__Guru* 84110 points

Gowtham Raj,

If you observe the same bit set in IER and in IFR, then the only explanation would be that the GIE bit in the CSR register is not set. The Wiki page that Brad references explains that "When you return from main() and BIOS starts its scheduler it will automatically enable global interrupts for you."

If CSR.GIE == 1 and IER.intbit == 1 and IFR.intbit == 1, then the ISR will be invoked and IFR.intbit will be cleared to 0.

In your main() function, do you stay in a while{} loop, or do you exit main() after doing all of your initialization? Returning from main() is when BIOS starts running and GIE will be enabled.

Which version of BIOS are you using? SYS/BIOS (also known as BIOS6) requires a discrete function call at the end of main() to start BIOS.

Regards,
RandyP

If you need more help, please reply back. If this answers the question, please click Verify Answer , below.

0 Gowtham Raj over 14 years ago in reply to RandyP

Prodigy 60 points

Hi Randy,

Thanks for your reply.

Yes i actually have a while(1) { ...} in my main( ) after doing all my initializations,so as you said there are no chances for the BIOS to execute.Then i have to manually set the GIE bit...?

And to add to it why is the BIOS execution scheduled at the end of main( ) it can be in the beginning..? is there any specific reason..?

0 Gowtham Raj over 14 years ago in reply to Gowtham Raj

Prodigy 60 points

May i please know how to externally access the CSR register.. to enable the global interrupt?

0 Brad Griffis over 14 years ago in reply to Gowtham Raj

TI__Guru*** 125430 points

If you wish to use BIOS the correct thing to do is to return from main and move your while(1) loop into a task. If you wish to ignore my suggestion then please see look for the cregister keyword in the C Compiler Guide.

0 Gowtham Raj over 14 years ago in reply to Brad Griffis

Prodigy 60 points

Thank you Brad and Randy,

I got my problem fixed.

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ISR not getting invoked