HP 16500B User Reference page 95

Example
A nal yzi ng Interrupt H andl i ng i n a C PU System
M ost m i cr opr ocessor pr ogr am s can be i nt er r upt ed by an asynchr onous
har dw ar e si gnal . Sof t w ar e desi gner s ar e i nt er est ed i n t he pr ocessor ' s
r eal - t i m e r esponse t o i nt er r upt s. I n par t i cul ar , you need t o answ er t hese
ki nds of quest i ons:
•
Does t he pr ocessor br anch t o t he pr oper i nt er r upt handl i ng r out i ne?
•
Ar e r egi st er s and st at us i nf or m at i on saved pr oper l y?
•
How l ong does i t t ake t o ser vi ce t he i nt er r upt ?
•
I s t he i nt er r upt acknow l edged pr oper l y?
•
Af t er t he i nt er r upt i s ser vi ced, does t he pr ocessor r est or e r egi st er s and
st at us i nf or m at i on and cont i nue w i t h t he pr evi ous r out i ne as expect ed?
Usual l y, sof t w ar e desi gner s w ant t o l ook at t he pr ogr am f l ow of t he
m i cr opr ocessor syst em ar ound an asynchr onous event .
A st at e anal yzer , coupl ed w i t h a pr epr ocessor and an i nver se assem bl er , i s
usef ul f or t r aci ng t he f l ow of a m i cr opr ocessor pr ogr am . A t i m i ng anal yzer or
an osci l l oscope i s desi gned t o t r i gger on asynchr onous event s l i ke edges.
I n t hi s exam pl e, use an osci l l oscope w i t h a sam pl e r at e f ast er t han t he
m i cr opr ocessor cl ock t o t r i gger on t he asynchr onous event and t o ar m t he
st at e anal yzer . Then use t he st at e anal yzer t o check t he addr ess of t he
i nt er r upt r out i ne. You m ay al so use t he st at e anal yzer t o see i f t he
m i cr opr ocessor i s pr oper l y ser vi ci ng i nt er r upt s and r et ur ni ng t o t he cor r ect
addr ess af t er each i nt er r upt r out i ne.
Intermodule Measurements
What Are Some Typical Intermodule Measurements?
7–15