JFT - Functional electronics testing without a single line of code

Testing of an embedded digital system, a combination of electronics and software,  has traditionally required some sort of embedded software specifically created for testing. A new testing technology makes these separate test versions redundant. This new solution is based on a combination of  JTAG Functional Testing -  JFT, and National Instruments ‘LabVIEW’.


Testing of an embedded digital system, a combination of electronics and software,  has traditionally required some sort of embedded software specifically created for testing. These test versions are downloaded to the product’s processor before testing is possible. ”A significant amount of work and project  time is  often spent on producing test versions of the embedded software and possibly FPGA code”, tells Senior Project Manager Ilpo Harjumäki.

”A new testing technology we have started to employ makes these separate test versions redundant. This new technology has been utilized within Etteplan for almost two years now” tells Ilpo Harjumäki proudly.

The new solution is based on a combination of  JTAG Functional Testing -  JFT, and National Instrumenst ‘LabVIEW’.

Based on JTAG

The JTAG/boundary scan pcb assembly test method is well-established. It is a separate function within the key ICs used in an assembley. When in use,  the relevant states (of device pins) are clocked to the outputs of the chained circuits using a serial bus. The input states are then read respectively and compared. However using the latest, essentially more flexible JFT  system from  JTAG Technologies a single pin or group of pins can be driven into a certain state to be read. With the addition of CoreCommander routines  users can also leverage the power of a microprocessor core to a desired value into the processor’s registers, setting up internal peripherals such as ADCs, DACs, PHYs and UARTS.

”It’s as if  this technology was made for us since Etteplan’s Procket testers support LabVIEW software”, praises Ilpo Harjumäki.

Easier with LabVIEW

”Input/output pins of the circuits and registers of the processors can be written to and read from using a LabVIEW program.  Device IO pins can be also used to implement a SPI or I2C bus for reading the sensors and controlling the embedded sub- circuits. We can, for example, read the value of an AD converter and write a desired voltage into a DA converter”, explains testing planner Janne Kari.

”And all this without writing a single line of embedded code”, rejoices Janne Kari.

”Using LabVIEW JFT  the interface with signals and pins is a generic one. Thus, a function is always called in the same way regardless of the electronic component used. Traditional testing program involves commands which vary depending on the manufacturer of the component or the embedded SW implementation”, explains Janne Kari.

It is due to this generic behaviour LabView JFT  test modules created for earlier projects can be reused and recycled.

As an example Janne Kari connects the USB port of a laptop through an adapter to the serial port pins of a JTAG compliant development board. Controlling an output pin on the development board using JFT he is able to flash an LED from the Labview application running on the laptop. (see video clip)

”We can test a completely ‘cold’ connection without a single byte of software code programmed”, he says.


Significant benefits and savings

”The latest LabVIEW JFT testing technique has already saved us significant work and costs and definitely speeds up the project lead time”, summarizes Ilpo Harjumäki.

Creating tests with LabView JFT software is many times simpler than producing dedicated embedded code. Errors tend to occur less frequently than in traditional programming, and when they do occurr, they are faster and easier to fix.

”There’s no going back!”, state both Ilpo Harjumäki and Janne Kari, almost with one voice.

Ilpo and Janne are eager to discuss more about JFT and test methods. they can be reached at [email protected] and [email protected].

Mick Austin can be reached at [email protected] or +358 50 597 6549

”It’s been a great experience working with Etteplan and introducing them to our novel LabVIEW JFT product. Seeing them achieve their goals in a timely manner shows how co-operative working produces the best results.”

Mick Austin, JTAG Technologies Ltd

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Teppo Välisaari
Teppo Välisaari
Director, Software & Embedded Solutions, Test Solutions