About interrupt handling

Hi all,

In ARM926EJ-S Architecture, If I am not using nested interrupts, do I
need to perform a write to IVR register?
>From the beginning, I started with the interrupt handling atmel provided
and did not question it, just understand what it does.
But now, out of curiosity, I tried not doing it (write to IVR) and it
works..
Why would one need it really? In the manual it says "This (Protected
Mode) is necessary when working with a debug system.", but I am not sure
what that should tell me exactly..

Best Regards,
Bekir Start a New Thread

Hi

> Why would one need it really? In the manual it says "This (Protected
> Mode) is necessary when working with a debug system.", but I am not sure
> what that should tell me exactly..

An access to EOICR pops the interrupt (also reading) ...
--
42Bastian

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Hi,

The EOICR register is clear to me, but in the code there is this piece:

/* Write in the IVR to support Protect Mode */
ldr lr, =AT91C_BASE_AIC
ldr r1, [lr, #BOOT_AIC_IVR]
str lr, [lr, #BOOT_AIC_IVR]

I don't know why they do this..

-----Ursprgliche Nachricht-----
Von: A... [mailto:A...] Im Auftrag von 42Bastian
Gesendet: Montag, 28. Juli 2008 15:19
An: A...
Betreff: Re: [AT91SAM] About interrupt handling

Hi

> Why would one need it really? In the manual it says "This (Protected
> Mode) is necessary when working with a debug system.", but I am not sure
> what that should tell me exactly..

An access to EOICR pops the interrupt (also reading) ...
--
42Bastian

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Hi,

I have a SAM9-L9260 board from Olimex, it has linux running from
nand-flash, and now I want to run linux from a sdcard.

First time to leard more about this, I think if I put a linux filesystem
on sdcard and say to u-boot that linux is there, it may works, correct
me if I am wrong.

So I need to learn how to put a linux filesystem into sdcard, may
somebody point me to a link or anything that can help-me.

Best regards

Paulo

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ICLI, Bekir (EXT) schrieb:
> Hi,
>
> The EOICR register is clear to me, but in the code there is this piece:
>
> /* Write in the IVR to support Protect Mode */
> ldr lr, =AT91C_BASE_AIC
> ldr r1, [lr, #BOOT_AIC_IVR]
> str lr, [lr, #BOOT_AIC_IVR]
>
> I don't know why they do this..

What is unclear about this:
(sam9260 referece manual)

The Protect Mode permits reading the Interrupt Vector Register without
performing the associated automatic operations. This is necessary when
working with a debug system. When a debugger, working either with a
Debug Monitor or the ARM processor's ICE, stops the applications and
updates the opened windows, it might read the AIC User Interface and
thus the IVR.
This has undesirable consequences:
• If an enabled interrupt with a higher priority than the current one is
pending, it is stacked.
• If there is no enabled pending interrupt, the spurious vector is returned.
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42Bastian

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Hi,

This is not targeted to SAM9 but you should get the idea.

http://www.avrfreaks.net/wiki/index.php/Documentation:AVR32_Linux_Developmen
t/Programming_an_SD_card_with_the_AVR32_Linux_file_system

just correct the addressing to match sam9 and you should be a the right
track. I have not done it myself. But should work

Jonathan

-----Message d'origine-----
De: A... [mailto:A...] De la part de
Paulo Silva(OpenSoftware)
Envoy 28 juillet 2008 10:04
: A...
Objet: [AT91SAM] Linux in sdcard.

Hi,

I have a SAM9-L9260 board from Olimex, it has linux running from
nand-flash, and now I want to run linux from a sdcard.

First time to leard more about this, I think if I put a linux filesystem
on sdcard and say to u-boot that linux is there, it may works, correct
me if I am wrong.

So I need to learn how to put a linux filesystem into sdcard, may
somebody point me to a link or anything that can help-me.

Best regards

Paulo

Start a New Thread