ARM Technical Support Knowledge Articles

USING INTERRUPT NESTING

Applies to: Advanced RTOS

Answer


Information in this article applies to:


QUESTION

I know that Advanced RTX by default uses the classic ARM interrupt mode which does not allow interrupt nesting on the IRQ level. However, the STMicroelectronics STR7 series has an interrupt controller that allows interrupt nesting. Can I use this interrupt nesting with ARTX?

ANSWER

You may use interrupt nesting in IRQ interrupt service routines as explained in the article CARM: NESTING INTERRUPTS.

Be aware that the interrupt routines use the task stack. Each nested interrupt uses at least 30 bytes extra on the user task stack (to save all used CPU registers). In the case that the interrupt is calling other functions, in addition to this 30 bytes, extra stack will be used. Therefore the stack requirements of your application will grow quite a bit.

We suggest keeping interrupt routines short. Instead, implement any complex functionality in the task functions of your application and use the methods of the Real-Time Kernel to exchange information.

Note that interrupt nesting is not just limited to the STR7 devices, but may also be used on other ARM device variants.

SEE ALSO

Article last edited on: 2007-01-10 13:17:39

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