Engineers designing 8- or 16-bit microcontroller-based products are prime candidates for a class of instruments known as mixed-signal oscilloscopes (MSO). Released in May 2000, Agilent's 54600 Series MSO combines the detailed signal analysis of an oscilloscope with the multichannel timing measurements of a logic analyzer. Users can simultaneously view two analog and up to 16 digital signals. This works well for debugging certain kinds of microcontroller problems that a conventional oscilloscope can't solve, like triggering on a mix of digital bus states and analog signals.
But why not instead purchase a relatively low-cost logic analyzer, such as the LogicWave, for debugging? Greg Peters of Agilent contends that customers will self-select the instrument. If they're already oscilloscope users who now have to do a microcontroller design for an appliance, such as a microcontrolled toaster, they will almost always self-select depending on where they're comfortable, which is the oscilloscope and added timing channels.
"If a customer has had experience with a logic analyzer in the past, maybe even some of what we call our big iron systems—the 16700 or 16500—but they don't have the budget, then they probably will drop down to a LogicWave because they're accustomed to using that tool and they appreciate state analysis, for example. And state analysis by us is synchronous clocking. It's capturing data when it's valid on the bus," Peters explains. "The MSO is really a popular product, though. It combines oscilloscope-viewing capabilities. You get two million data points that you can pan and zoom around very rapidly to find the problem. Then you can link it back to the timing domain on other channels to see if you can uncover the root cause of the problem."