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Hello,

If i do a sei instruction and if an interrupt should occur. When i do a CLI instruction if this interrupt is treated or is it forgotten?

Thank you very much

Regards

[Non-text portions of this message have been removed]
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Pascal wrote:

> Hello,
>
> If i do a sei instruction and if an interrupt should occur. When i do a
> CLI instruction if this interrupt is treated or is it forgotten?

Peripherals flags is what does remember pending interrupts. For example RTIF
bit in CRGFLG register is what doesn't forget about RealTimeInterrupt. TFLG1
and TFLG2 registers is what doesn't forget about timer interrupts. SEI and
CLI don't affect any periferal flags, after CLI pending interrupts will be
serviced.

Edward

>
> Thank you very much
>
> Regards



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--- In 6...@yahoogroups.com, "Pascal" wrote:
>
> Hello,
>
> If i do a sei instruction and if an interrupt should occur. When i
do a CLI instruction if this interrupt is treated or is it forgotten?
>
> Thank you very much
>
> Regards
>
> [Non-text portions of this message have been removed]
>

Any interrupt flags that are still present when the interrupts are re-
enabled will cause an immediate interrupt. You don't say which
interrupt you are concerned about but I don't think there are any
that don't keep their flags set until cleared by writing to the flag
or reading the appropriate status and/or data registers.



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--- In 6...@yahoogroups.com, "Edward Karpicz" wrote:
> Peripherals flags is what does remember pending interrupts.

Also keep this in mind when you 'cli' for the first time. Sometimes an
interrupt was already pending just because of a random even on
powerup, so people often clear the pending flags before the first
'cli' to make sure it won't immediately call an unwanted interrupt.



(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Thank you for help. I understand how it works.

Regards

----- Original Message -----
From: Pascal
To: 6...@yahoogroups.com
Sent: Wednesday, March 14, 2007 5:02 PM
Subject: [68HC12] SEI instruction and interrupt
Hello,

If i do a sei instruction and if an interrupt should occur. When i do a CLI instruction if this interrupt is treated or is it forgotten?

Thank you very much

Regards

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]


(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

--- In 6...@yahoogroups.com, "Pascal" wrote:
>
> Thank you for help. I understand how it works.

Good stuff.
There are a few gotchas, there is only one flag for these registers, a second interupt request occurring in the same register before the first one is served is problem.

Some routines operating on say I/O registers should not be interupted, do a sei before the operation and clear it when done.

Also do not enable interupts inside IRQs etc unless you know you have time to handle it, stacks are gone in a wiffy.

Good luck

Theo

> ----- Original Message -----
> From: Pascal
> To: 6...@yahoogroups.com
> Sent: Wednesday, March 14, 2007 5:02 PM
> Subject: [68HC12] SEI instruction and interrupt
> Hello,
>
> If i do a sei instruction and if an interrupt should occur. When i do a CLI instruction if this interrupt is treated or is it forgotten?
>
> Thank you very much
>
> Regards
>
> [Non-text portions of this message have been removed]
>
>
>
> [Non-text portions of this message have been removed]
>



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