Agilent 5990-8359EN Selecting the Right Scope for Protocol Analysis Applications - Application Note c2014061 free download

File name 5990-8359EN Selecting the Right Scope for Protocol Analysis Applications - Application Note c2014061

Keysight Technologies Selecting the Right Oscilloscope for Protocol Analysis Applications Application Note Introduction Serial buses are pervasive in today's electronic designs to provide critical communication between ICs, subsystems, boards and systems. I2C and SPI have found their way into a broad array of chips and peripherals including FPGAs, a variety of I/O, ADCs, sensors, ASICs and processors. JTAG serial buses, test chips and boards also provide debug ports for microprocessors and other integrated circuits. CAN, LIN and FlexRay enable noise-immune communication networks for automotive and industrial products. USB ports have become pervasive on mobile and other consumer products, and PCIe has gained a foothold by passing large amounts of data quickly. Even legacy serial buses like RS-232/485/485 and MIL-STD 1553 continue to prosper despite their age. Low cost, minimal pin usage and a protocol layer that eases software implementation make serial buses ideal for a wide variety of applications across a range of industries. All major oscilloscope vendors now offer scope-based protocol applica- tions that enable you to gain faster and better insight when debugging systems with serial buses. These applications let oscilloscopes trigger on and display packets in addition to parametric signal detail. They help you answer questions, including "How are the devices on each end of the bus negotiating the link?" and "What values are being passed on the bus?" With the right combination of oscilloscope and protocol application, you can resolve issues quickly, saving days to weeks of time. Although all major scope vendors offer protocol decode and triggering applications, the applications vary in capability and quality. When evaluating a new oscil- loscope that will include protocol applications, you should consider the following six questions. 1. What protocols are supported and to what degree? Make sure the oscilloscope vendor has support for protocols that you currently use or are likely to use in the near future. It's easy to check a Web page to see if the protocol you are interested in is supported on a particular scope. Getting a trial license is a great way to make a determination. You need to pull up the application on an oscilloscope or look through detail in the datasheet, to deter- mine how well the particular protocol is supported. Figure 1. View product web pages to see if the protocol you are interested in is supported on a particular scope.