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MSP430 Interrupt issues

Posted by Julio Armijos on April 24, 2011
Good Evening all,

I have successfully ported the original MSP430F5438 demo built for CCSv4 into an MSP430F6638, but I am now having difficulties with the interrupt routine that comes from one of the push buttons. I have modified the routine so that it uses port P1.0 of the chip since that is where I have a button open, but as soon as the interrupt routine starts, FreeRTOS behaves strangely and does not return to the routines nor displays data on the screen. Does anyone have any idea on what could be happening here?

I find it strange that the scheduler continues to work, and if I press the interrupted button it will go back to the interrupt subroutine, but nothing happens after that.

The only changes that I made to the code was in the main.c file were I modified the interrupt vector to use port1.

Any help in this issue will be greatly appreciate it.


RE: MSP430 Interrupt issues

Posted by Richard on April 24, 2011
If the interrupt fires, but only once, can you check that the interrupt handler is clearing the correct interrupt bits.

RE: MSP430 Interrupt issues

Posted by Julio Armijos on April 29, 2011
Hello Mr. Barry,

Thank you for your prompt reply. I have checked the handler, and it is clearing the proper interrupt bit. The interrupt that I am using is located in port 1. To be exact, it is at P1.0 of the MSP430.

I am new to the RTOS concept, and my understanding is that the kernel uses some interrupts in order for it to run properly. Is there any chance I might be clearing one of those interrupts by using port 1 in my project?

RE: MSP430 Interrupt issues

Posted by Richard on April 29, 2011
The MSP430X port only uses a single timer interrupt. The timer used is configured by the application callback function (defined in the application, not the kernel) vApplicationSetupTimerInterrupt(). In the provided demos, vApplicationSetupTimerInterrupt() uses the TA0 timer. I don't think clearing a port pin would in any way effect that timer.


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