Uninitialized ISR Vector detected

What it means

The MSP430 microcontroller dedicates a segment of the memory for the interrupt sub-routine (ISR) vectors.This segment of memory contains the addresses for the ISR associated with the corresponding interrupts, allowing for the interrupt to trigger the ISR vector and executing the ISR defined at the stored addresses. Even if some of these interrupts are not used in the application, the ISR vectors should be initialized and assigned properly to ensure all interrupts, whether application-intended or accidental, can be vectored,captured, and executed properly to prevent any erroneous behaviors in the application.

Risks, Severity

An uninitialized ISR vector when triggered could lead to jumping to unknown addresses, execution of erroneous code which at the very least could lead to application crashing, unexpected application behavior, or more severely memory erasure or electrical damage.

Why it is happening

At least one of the ISR vector was detected to be un-initialzed.

Remedy

• Initialize all of the ISR vectors available to your device. Refer to the device datasheet and header files for the exact list of ISR vectors available to your device.

#pragma vector=unused_interrupts
__interrupt void ISR_trap(void)
{
/* For debugging purposes, you can trap the CPU & code execution here with an 
  infinite loop */
while (1);

/* If a reset is preferred, in scenarios where you want to reset the entire system and 
  restart the application from the beginning, use one of the following lines depending
  on your MSP430 device family, and make sure to comment out the while (1) line above */

/* If you are using MSP430F5xx or MSP430F6xx devices, use the following line
  to trigger a software BOR.   */
PMMCTL0 = PMMPW | PMMSWBOR;          // Apply PMM password and trigger SW BOR

/* If you are using MSP430 devices that are part of the 1xx/2xx/4xx families
  use the following line of code to cause an access violation which results 
  in a PUC reset */
WDTCTL = 0;                          // Write to WDT with a wrong password
}

Note that the recommended ISR handling codes are different depending on the MSP430 platforms (1xx/2xx/4xx use Watch Dog Timer (WDT) to cause a Power Up Clear (PUC) reset, 5xx/6xx can also use the Power Management Module (PMM) to trigger software Brown Out Reset (BOR).

• Suppress the warning: initializing all interrupt vectors is good code practice and it is highly recommended. However, if you insist on leaving the unused interrupt vectors uninitialized or have other less common purposed for these memory addresses, you can turn off the warning by adding the warning code #10374 to the diagnostic message suppress list.

Code Example

Refer to our following code example for guidance on using and initializing interrupt vectors.

processors.wiki.ti.com/index.php/File:Msp430_initialize_unused_interrrupt_vectors.zip

See the rest of the code examples for all MSP430 devices here!

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