Interrupts on 5282

Priority level 7 does not disable level 7 interrupts!

From the MCF5282 ColdFire Microcontroller User's Manual
section 10.1:
"If the priority level is greater than the SR[I] field
at the sample
point, the processor suspends normal instruction execution
and initiates
interrupt exception processing. Level 7 interrupts are
treated as
non-maskable and edge-sensitive within the processor, while
levels 1-6
are treated as level-sensitive and may be masked depending
on the value
of the SR[I] field.".


-----Original Message-----
From: ColdFirelists.wildrice.com [mailto:ColdFirelists.wildrice.com]
On Behalf Of William Wolthuis
Sent: Friday, April 07, 2006 12:31 PM
To: Steven L. Zook
Subject: [ColdFire] Interrupts on 5282

I was having problems using interrupts and discovered that
the interrupt
priority level for the main routine was set to 7 in the
status register.
I set the level to be a lower value than the interrupts I
wanted to use
and this allowed my interrupts to work correctly.  This
makes sense
because "interrupts are inhibited for all priority
levels less than or
equal to the current interrupt priority."  But I
don't understand why
the main routine was set to interrupt priority level 7 by
default since
this would seem to disable the use of any interrupts.  Can
anyone tell
me why this would be?

 

William Wolthuis

RJC Enterprises

 

 

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