RE: [ECOS] Enable EDB7xxx interrupts

["Trenton D. Adams" <tadams at extremeeng dot com>]

> >I did test the EINT1 interrupt on the CPU as you suggested with the 
> >multi tester by pulling it low, and fired just fine.
> 
> OK, that means your software is good, but we still haven't 
> narrowed the 
> problem down beyond these possibilities:
> 
> * PS6700 not configured correctly to generate interrupts
> * PS6700 configured correctly and generating interrupts, but those 
> interrupts not [electrically] making it to the CPU
> * PS6700 fried

Have you ever seen a device that shows that it's generating an interrupt
by looking at it's internal registers, but the actual interrupt is not
making it to the CPU?

> >Yep, already did that, a jumper is required for the FIQ, but not the 
> >IRQ line.  The FIQ jumper has been on the entire time however.
> 
> If the line is tied to another outputs from a different 
> device, or has an 
> overly aggressive pullup/pulldown then the 6700 might not be 
> able to pull 
> the CPU's input high/low enough to assert an interrupt 
> request if the other 
> device's output is not tristated. When you poked it with your 
> wire, you 
> forced the issue.
> 
> If possible it could be instructive to isolate the int out 
> pin(s) from the 
> 6700 and see if they show activity when electrically isolated 
> from the rest 
> of the circuit.
How would you do this when they are wired into the board?