# AT91SAM7S256 modes in FreeRTOS

**URL:** <https://forums.freertos.org/t/at91sam7s256-modes-in-freertos/1476>\
**Category:** Kernel\
**Created:** [February 26, 2009, 9:30am UTC](https://forums.freertos.org/t/at91sam7s256-modes-in-freertos/1476 "2009-02-26T09:30:22Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [February 26, 2009, 9:30am UTC](https://forums.freertos.org/t/at91sam7s256-modes-in-freertos/1476/1 "2009-02-26T09:30:22Z")

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**[aturowski](https://sourceforge.net/u/aturowski/)** wrote on [Thursday, February 26, 2009](https://sourceforge.net/p/freertos/discussion/382005/thread/445934f2/#a253):

Hi all!!!  
I’ve got two questions:

1) Could you please tell me, which ARM processor modes are used during execution of which parts of FreeRTOS. I mean which mode is used during for example scheduler execution, semaphore take etc.

2)Could you also please tell me what are the minimal stack sizes for these modes and if stacks for all processor modes has to be allocated and/or initialized?

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [February 26, 2009, 10:50am UTC](https://forums.freertos.org/t/at91sam7s256-modes-in-freertos/1476/2 "2009-02-26T10:50:33Z")

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**[davedoors](https://sourceforge.net/u/davedoors/)** wrote on [Thursday, February 26, 2009](https://sourceforge.net/p/freertos/discussion/382005/thread/445934f2/#a253/a4ec):

For stack sizes check the demo apps.

Main is called from Supervisor mode. Supervisor mode and IRQ mode are both used for context switching. Tasks run in System mode.

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**Author:** ![system](https://d2v6vdsk2p900z.cloudfront.net/original/1X/7fc8fdb729c645aab5b20282bbe34e57cb407be6.jpeg) [@system](https://forums.freertos.org/u/system)\
**Post date:** [February 26, 2009, 2:40pm UTC](https://forums.freertos.org/t/at91sam7s256-modes-in-freertos/1476/3 "2009-02-26T14:40:47Z")

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**[aturowski](https://sourceforge.net/u/aturowski/)** wrote on [Thursday, February 26, 2009](https://sourceforge.net/p/freertos/discussion/382005/thread/445934f2/#a253/a4ec/d8f1):

Thank you for information.