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Hitachi H8S interrupt handling
- From: "Uwe Kindler" <uwe_kindler at web dot de>
- To: <ecos-devel at sources dot redhat dot com>
- Date: Sun, 21 Sep 2003 14:41:23 +0200
- Subject: Hitachi H8S interrupt handling
i'm currently porting eCos for the EDOSK 2674 board from Hitachi and have a
question about interrupt handling.
If the Hitachi H8S microcontroller works in interrupt control mode 2, then
an enhanced interrupt priority management is possible. If an interrupt
occures then only the interrupt level of this interrupt and all lower
interrupt levels (there are 8 different interrupt levels) are masked
immediatelly after the interrupt occurence.
That means interrupt nesting can happen if interrupts with a higher priority
level occur immediatelly after the current interrupt.
I read the "Default Interrupt Handling" part of the eCos Reference Manual
carefully and in point 5 is written:
"Re-enable interrupts to permit nesting". But I did not found anything about
disabling interrupts before.
So this is my question: If an interrupt occures, should i disable all
interrupts immediately and re-enable higher priority interrupts
according to the manual. Or what is the best way to treat these 8 different
Thank you very much and best regards,