> Global interrupts      = enabled
> Interrupt on RB0/INT   = enabled
> Interrupt on TMR0      = enabled
>
> Situation (example):
>
> Timer generates an interrupt.
> ISR checks for cause and determines it was TMR0.
> Services interrupt for TMR0 cause.
> Clear TMR0 flag
> RETFIE
>
> Sometime during the ISR (after checking cause), RB0/INT signals an
> interrupt. What happens next ?

The interrupt flag went true as soon as the RB0 edge was detected.  However,
interrupts are disabled until the RETFIE instruction.  As soon as they are
re-enabled by RETFIE you will get another interrupt.  It is perfectly OK to
write your interrupt routine to handle only one interrupt at a time.  If a
second interrupt condition occurs while the first is being handled, you will
just get another interrupt immediately after the first one.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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