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A hands-on look at the feature-packed SP209i nine-channel industrial logic analyser, including a simple example application to demonstrate some of the analyser features.
The IKALOGIC SP209iis a feature-rich industrial logic analyser, packed full of goodies and interfaces including RS232, RS485, CAN and LIN bus transceivers that can be multiplexed onto the traditional logic analyser input channels.
What is a Logic Analyser?
A logic analyser is an instrument used to capture and display multiple signals from a digital system and provide an insight into the operation of the connected system.
Logic analysers can perform multiple functions with captured data, including (but not limited to): protocol decoding based upon the captured data, generating state machine traces, producing timing diagrams and can sometimes even produce assembly language based on observing a CPU bus.
Historically, logic analysers used to be rather large machines, often taking up considerable bench space (commonly the size of cathode-ray oscilloscopes), but now thanks to the advent of powerful PCs and microcontrollers they can be as small as a chunky USB stick.
Logic analysers typically offer powerful trigger options, ranging from triggering on a pin going high to triggering on an entire protocol decode, such as a specific Ethernet frame going by or a HTTP packet being decoded. Various capture modes can be set — typically either a “timing” mode, where input signals are sampled on a regular basis (either from an internal or external timebase), or a “state” mode where signals can be defined as clocks, then the analyser triggered on either the rising or falling edge of the clock signal.
IKALOGIC have produced a surprisingly powerful nine-channel logic analyser in a deceptively small package that is 85x60mm, and weighing no more than 105 grams — perfect for using on a tightly packed desk.
Features of the SP209i include:
- Nine input channels — these can be used as nine individual inputs or multiplexed onto the industrial transceivers
- One RS232, two RS485, one CAN & one LIN receiver
- RS422 full-duplex support by combining both RS485 receivers
- 200MSPS sample rate with all nine inputs in use
- 50MHz digital input bandwidth
- External clock rate of up to 50MHz in state mode
- External trigger input & output via SMA connectors
- 2Gb of on-board sample memory, in case the USB connection cannot keep up with a given sample rate
With an input voltage range of ± 25V, there is plenty of headroom for connecting to higher voltage logic — including breathing space for things such as accidentally shorting an input to a supply rail.
Included in the box is the logic analyser itself, a one metre USB lead for connection to a PC, and a rather nice set of micro grabber probes suitable for grabbing onto small component leads.
As is the case with other instrumentation, having good quality leads can make or break the user experience. Luckily the leads supplied by IKALOGIC are a good quality flexible silicone wire, with a small cable comb snapped over to help keep everything organised.
The generous onboard sample memory means that the SP209i is capable of sampling all nine channels at 200Msps — perfect for watching higher speed buses. Typically, logic analysers either store samples on embedded memory ready for later downloading — allowing for high capture rates but with limited sample depth; or the samples are streamed straight over a USB connection as fast as possible — offering practically unlimited sample depth (only restricted by the host computer memory) but with the disadvantage of having limited bandwidth and channel availability.
IKALOGIC have taken a mix of both approaches by streaming samples at the full 200Msps into the on-board memory, then compressing the samples and sending them over USB as quickly as possible. This reaches a nice compromise between recording time and channel count with IKALOGIC saying this results in being able to “capture dozens of minutes of logic signals activity on 9 channels at 200 MSPS”.
Included in the SP209i are two “FlexiTrig” trigger engines, capable of multiple trigger modes including edge, pulse, timed logic sequence, protocol-based and an external trigger source. Additionally, the two trigger engines can be cascaded in various permutations of one then another, or any order.
The external trigger output on the SP209i is always active and features a low delay between the external signal capture and the trigger output being generated. As shown in the diagram above, the trigger delay is generated in two parts but is only thirty nanoseconds long. A similar delay is present on the trigger input, but with a delay of only twenty nanoseconds.
IKALOGIC provides a tool called ScanaLogic to drive their logic analysers that is available on not only Windows, but MacOS and Linux too. Also available from the website is an API for interfacing with the SP209i at a lower level — ideal for integration with an existing test or automation system.
Getting the software installed on Windows is a breeze — the installer includes the device drivers which are installed as the main installation progresses.
With the software installed, we launched ScanaStudio and were presented with a screen prompting us to download various protocol decoders. After downloading the protocol decoders, we’re prompted to create a new workspace — workspaces can be saved which keeps the logic analyser settings, and anything else such as protocol decoder settings.
By default, the logic analyser is set up for the maximum sample rate, with no other options enabled. The user interface is laid out intuitively, with signals on the right and various settings on the left.
If we leave the settings as-is, a total capture time of one second is computed. This can be changed by adjusting the number of samples taken, which adjusts the capture time.
Feeding a 1Mhz square wave into channel one, we can click “Start” and start a capture that automatically ends after the capture time period expires. Zooming in on the signals shows clean trigger edges, and a measurement can be added to calculate the frequency of the signal — a nice 1MHz.
To demonstrate using one of the protocol option triggers, we flashed an Arduino with a simple UART “Hello world” firmware that prints the text “Hello world” over the serial connection.
First, a protocol has to be added to be able to use the protocol trigger. This is as easy as heading to the “Protocols” and adding a decoder. A window then pops up that walks through the initialisation of the decoder, with many options that can be configured.
A trigger channel can then be set up to watch for a UART protocol decode, and can additionally be set to trigger with different options such as on a specific word or byte.
With the trigger configured, “Start” can be clicked and the capture begins once the trigger conditions are met. As can be seen in the above screenshot, the protocol decode is overlaid on top of the trace (the hex decode was turned off for visibility) and both can be examined at the same time.
In this post, we’ve taken a look at the IKALOGIC SP209i industrial logic analyser, the impressive specifications and demonstrated an example of the powerful software capabilities.