An oscilloscope allows you to observe changing voltages. It gives you important answers, ranging from, "Is this signal changing?" to, "What are the timing relationships between these signals?"

A multimeter allows you to know the relatively precise voltage at a given node in a circuit, but it seems to me that it's a lot more useful to know the relative state (high or low) of a signal when you're troubleshooting a microcontroller circuit. Of course the multimeter will help when you're working with ADC or DAC but unless they change very slowly, the multimeter won't really give you useful information.

Time after time we see situations on the 8052 or Chat forum that take many days to settle, when an oscilloscope would have resolved the question within minutes. You don't have to have a modern and costly instrument. Most problems can be solved with instruments available on eBay for about $200US or even less. You should have an instrument with bandwidth of at least 100 MHz, two or more channels, two timebases, in general, features comparable with those of, say, a Tektronix 465. Those PC-based instruments often suffer in precision or in bandwidth, and lack the delayed sweep. Keep in mind that the "bandwidth" of an analog 'scope is the frequency at which the signal is attenuated by 3db. If you don't know what that means, a little investigation on Google will help.

It's often possible to obtain an oscilloscope that will, in large part, take the place of, or include, a multimeter. One example would be a Tektronix 475A with DM44. I directed a friend who was considering a multimeter to one of these and he found it cost less than a good new multimeter would have cost, yet did much more to help him than a multimeter would or could have done.

RE