RoadTest: Digilent Digital Discovery with High Speed Adapter
Author: jpnbino
Creation date:
Evaluation Type: Development Boards & Tools
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: I have an old Logic8 but it is not that powerful so I can compare to Digital Discovery.
What were the biggest problems encountered?: Documentation lacks.
Detailed Review:
Introduction
Hi, as an electrical engineer who got inside the embedded system world, very early I started learning about the importance of using good tools to have the work done given that I had some troubles that a logic analyser or an oscilloscope could easily solve.
So I promptly I started using a logic analyser (Logic8) as part of my development tools which have helped me a lot for about 4years. I can surely say that without such an instrument my job as an embedded developer was bound to fail.
So, one day I was randomly swiping on facebook when I saw an ad of element14 about RoadTest, usually I just ignore but this time I didn't. At that day Digital Discovery was openned for application. I applied myself as I want to use the tool in my professional life.
Participate of the RoadTest was a very nice experience that also teached me how to record videos, why should I master the tools I have and how to share experience.
Enough talk. Let's get on the road.
Unpacking
In this section I show the unboxing of my Digital Discovery.
I received a medium size cardboard box with everything inside it. The products inside were all covered by bubble wrap. There wasn't even a single detail of bad transport situation. Everything was in perfect state.
Cardboard box content:
- Digital Discovery plastic box with: a digital discovery, a micro usb cable, a 2x16 flywire connector ,a 2x6 flywire connector;
- Plastic Bag with: High speed adaptor board and 16 twisted pair cables.
The unboxing is reported from figure 1 to figure 8. See below:
Figure 1: Cardboard Box
Figure 2: Equipment covered in bubble wrap
Figure 3: Resistent plastic bag of high speed adapter and twiste pair probes
Figure 4: Digital Discovery box
Figure 5: Contents of cardboard box
Figure 6: All parts of the roadtest kit
Figure 7: Details of HighSpeed adapter
Figure 8: Detail of high speed a probe
Some curiosity
As I like PCB's someway artistic I openned my Digital discovery to take a closer look and see the floor planning and some tracks along their ways. I found signs of length matching, probably DDR3 ( Logic analyzer buffer )tracks and signs of a good floor planning. By the way, I'm thinking about change the value of the status led resistors (R189, R191,R193) , sometimes they look too bright.
Led circuit link: https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manual#leds_and_ddr3_memory
Of course, my eyes could capture a better visual of the parts but the images are still good, see figure 9, figure 10 and figure 11.
Figure 9: Digital Discovery disassembly
Figure 10: Digital discovery top side detail
Figure 11: Digital discovery Bottom side detail with length matching tracks visible
A detail about digital discovery is that it is implemented with a FPGA, the Spartan-6 from Xilinx. So it is a good idea for those who wants to know a little bit more about the tool search for Spartan-6 documentation, but it's not mandatory to work with digital discovery.
Videos
This series of videos on this RoadTest review shows the digital discovery from inside the box to hands on.
Part 1 - Inside the Box
https://youtu.be/BUfd_oksqfQ?list=PL5QjlwGPgo8_msFBKmJaOEJBfUmfhQs4N
Part 2 - Waveforms Overview
https://youtu.be/dRjAppiYtMQ?list=PL5QjlwGPgo8_msFBKmJaOEJBfUmfhQs4N
Part3 - Supplies instrument
https://youtu.be/TKFTNRlmIQM?list=PL5QjlwGPgo8_msFBKmJaOEJBfUmfhQs4N
Part 4 - Logic, Patterns and StaticIO instrument Part1
https://youtu.be/YcmVE0UUfp0?list=PL5QjlwGPgo8_msFBKmJaOEJBfUmfhQs4N
Part 5 - Logic, Patterns and StaticIO instrument Part2
Part6 - Script
Part7 - Protocol Analyser ( UART and I2C )
Comparing related products
Gather various products that performs logic analysing, pattern generation and comparing them is not that easy. So the following table is an approximated comparison since every analyser has its exclusive feature. If you want to buy one consider carefully your needs, for instance, many of them have a lot of protocols decode, or really high sample rate, or accepts RS485 logic levels directy.
| Logic Analyser | Pattern Generator | N of Channels | Sample Rate | Memory | Price (US$) | Website |
|---|---|---|---|---|---|---|
| Digital Discovery | YES | 8/16/32 | 800/400/200 | 256MB | 199.99 | Digital Discovery: Portable Logic Analyzer and Digital Pattern Generator - Digilent |
| SQ200 | YES | 4 | 200 | 16MB | 174.78 | https://ikalogic.com/pages/scanaquad-logic-analyzer |
| IO-3232B | YES | 16/32 | 400/200 | 8MB | 1.399 | USB Logic Analyzer | USB Pattern Generator|IO-3200 |
| LAP-C 16128* | NO | 16 | 100 | 64 | 135,00 | https://www.amazon.com/Zeroplus-LAP-C-16032-16-channel-Analyzer/dp/B0027QRPIA/ref=sr_1_2?s=industrial&ie=UTF8&qid=150736… |
*Logic Cube analyses varies mainly due to protocols decode
Some difficulties
I had trouble to find information about the operation of logic instrument, like better explanation of how does noise option works, how buffers works. Also, I didn't find information on how does the use of weak pull ups in DIN connector affect inputs sensibility. And, to understand the slew rate option "quiet" I had to refer to Xilinx Spartan6 documentation.
Conclusion
Digital discovery is by far a must have tool for embedded design. The price is affordable for a hardware that makes the job done, for the same performance in other product one may pay twice or higher ( e.g: IO-3200 Logic Analyzer, Pattern Generator starts at $750,00) . Also, the software is easy and the script feature is a plus. For an improved experience more effort should be made by Digilent around examples and documentation.
References
1 - https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manual
2 - https://reference.digilentinc.com/reference/instrumentation/digital-discovery/start
3 - https://forums.xilinx.com/t5/Spartan-Family-FPGAs/What-is-QUIETIO/m-p/4190
4 - https://www.xilinx.com/support/documentation/user_guides/ug381.pdf
Top Comments
Hi,
There is a logic analyzer tutorial here: https://reference.digilentinc.com/learn/instrumentation/tutorials/ad2-logic-analyzer/start
Hi,
Digilent Digital Discovery with High Speed Adapter - Review is complete. I forgot to say, but it is ready.
After finished, I kept using my Digital discovery and I have been learning more about it and…
HI,
I'm doing the fine tunning. So, to be in schedule I already posted it to not miss deadline.