Hey all,

What i told Dave on Wed. was wrong. (Thinking of the AVR.)

Might be better off anyway with the 32-bit timer capture function. I
think these will do what you want, and you get 8 of them. (Two timers
four each.)

 > Note: see page 20 of the manual (
 > http://www.keil.com/dd/docs/datashts/philips/user_manual_lpc214x.pdf) for
 > EINT details.
 > So, in diging into the details of the LPC2148, I've found that it has only 4
 > external interrupt lines. Each interrupt can be configured to trigger from a
 > couple of pins (and maybe the same interupt from multiple pins, not sure
 > yet). With respect to when the external interrupts trigger, this is
 > configurable, but in reading thru the manual, it looks like you can only set
 > it to positive or negative going edge, not on change (on change would be
 > nice for the quadrature encoder).
 > Ideally we'd have 5 external interupts, some of which would trigger on
 > change (quadriture ints), others on positive edge (hall sensors), however I
 > don't think were going to have that luxury with the LPC2148.
 > Technically, four rising edge interupts would work (3 hall sensors, 1
 > quadriture), however that means less resolution on the RPM of the table,
 > which will imply reduced ability for the PID loop to smothly react at low
 > RPM.
 > What are your thoughts on this. Theres a million ways to do this, but what
 > has the best mix of quick, easy, maintainable and will satisfy our
 > functional requirements?
 > Thoughts?

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