Digilent ARTY S7 Dev Board (Xilinx Spartan 7) - Review

Table of contents

RoadTest: Digilent ARTY S7 Dev Board (Xilinx Spartan 7)

Author: asher.bsher

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?: Arty A7 - Based on Artix-7 Family of FPGA https://store.digilentinc.com/arty-a7-artix-7-fpga-development-board-for-makers-and-hobbyists/ Arty Z7 - Based on Zynq-7000 https://store.digilentinc.com/arty-z7-apsoc-zynq-7000-development-board-for-makers-and-hobbyists/

What were the biggest problems encountered?: 1. Vivado Design Suite is a very heavy and resource consuming application. Recommend a fast and powerful PC/Laptop to begin with. 2. DSP System on the board is not easily accessible. Requires paid tools to link MATLAB to design flow.

Detailed Review:

DIGILENT

ARTY S7 BOARD REVIEW

 

ASHER SURANJITH JAYAKUMAR

Official Roadtester for Element14

 


  1. Introduction
  2. About the Board
  3. ARTY S7 and XILINX
  4. Vivado Design Environment
  5. Pmods
  6. Final Comments
  7. Disclaimer
  8. Project: SPDIF Audio Reciever –IN PROGRESS

                  

 

INTRODUCTION

Hey there, welcome to the official Roadtest review of the Arty S7 board by DIGILENT. Brought about by element14, this review is a result of coming together of many knowledgeable electronics engineers’ minds. Created to educate and inspire a community of great minds to do greater things. As an official Roadtester for this board, I wish to deliver this knowledge in a logically informative manner and cover all aspects of this device. So, first of, thank you Digilent and element14 for seeing me fit for this task and from the progress I’ve made I must say this is going to be more or less a positive review and I aim to highlight the strong capabilities of the board and get deep into its roots thereby creating an in-depth study, and more importantly share the knowledge and serve the main cause for this whole Roadtest Review.

Here we go.

 

About Me

Since this is going to be quiet the journey ahead, I thought its best you get to know me first(Or atleast the bare minimum that’s necessary).

 

I am Asher Suranjith Jayakumar, An Electronics Engineer. I work as a Product Engineer and Chief Operations Officer(COO) for AV TRONICS a power conditioner manufacturer for high end audio equipment.

Parallely, I am a musician. I play the guitar and the violin, practice songwriting as well as recording. As a professional, I am a trained audio engineer with deep audio programming, design and system engineering skills.

 

About the Review

Purpose of this document: An in depth study of the board based off a project, and a final review of the product.

I wish to add a little more insight on the board and provide this is a ‘Guidelines to the Arty S7’. Therefore this shall be something of a series, with each part covering a module. I hope to expertise on the Digilent board and Xilinx processor and provide extensive information on all aspects and conclude each module with a review on the same.

I hope to see you for the next few months as I share every step and would be more than willing to assist you further in your projects with debugging and what not.

So if you’ve made it through the first page and you’re curious as to what the hypes bout, just click on the link and get yourself the DIGILENT ARTY S7 development board, an incredible piece of technology created by DIGILENT.

https://store.digilentinc.com/arty-s7-spartan-7-fpga-board-for-makers-and-hobbyists/

Alright, enough talk, let’s get nurding already!

 

The DIGILENT ARTY S7

 

ABOUT THE BOARD

The DIGILENT ARTY S7 is a development board based on the Spartan-7 family of FPGAs developed by XILINX. The board is aimed at electronics hobbyists with beginner to intermediate level development skills. Digilent has done well in delivering a hobby grade development kit with such incredible capabilities and functionalities.

 

Image 01: DIGILENT ARTY S7-50

 

 

What’s on the board?

  1. BOARD NAME: ARTY S7-50
  2. FPGA: XILINX XCS50-1CSGA324C of the Spartan-7 Family is the lower mid range of their cost-optimized solutions. The Spartan is designed for high performance per watt meaning they are best implemented for systems that are less processing intensive but are power conservative in utility. So if you were developing for mass production this is the chip you probably might want to consider for obvious reasons. But as a hobby grade this a great processor that this board be built on.
  3. Pmod interface units: This is the whole reason why this board even exists. Digilent have a created a platform for ADD-ON modules for their boards, much like any other module types for development boards but with a very extensive range, which includes Arduino and chipKIT platforms. So here we have the Xilinx FPGAs, the Digilent Pmods, Arduino and chipKIT platforms coming together to create new possibilities which is a an A right there.
  4. 128 Mbit SPI Flash
  5. 256 Mbit DDR3 RAM
  6. 100MHz Clock
  7. Multiple Port I/O Pins
  8. 2 RESET Buttons
  9. 4 User Buttons
  10. 4 Slideswitches
  11. 4 LEDs and 2 RGB indication lights
  12. USB Port

 

  Image 2: Block Diagram

ARTY S7’s Spartan-7 Series

The board is designed around the core Xilinx FPGA –Spartan 7 Family of Processors. Among the entire portfolio of Xilinx FPGAs Spartan 7 is the entry level processor, low power consumption-high performance per watt to be more precise. So, the processor fits best for hobby grade or first time Xilinx users. To be a little critical on my review, the board boasts bout features which may not be easily accessible as the other processors or boards in the 7-series.

XILINX FAMILY OF FPGAs

  1. Virtex family
  2. Kintex
  3. Artix
  4. Zynq
  5. Spartan family

So to speak to the Spartan is series is at the bottom range of processors offered by Xilinx. The board itself is a lightweight release from both Digilent and Xilinx. But here is the catch – although by first impression the board seems to be on the entry level of things, if you are a product designer and are in the component selection phase of your project, the most critical design considerations kick in which are-cost, complexity, power consumption, performance and efficiency. And regardless of how carefree you were during your research stage, the production stage requires you to pick your components from the low power consumption section of the portfolio offerings. But once again you would rather have the high performance component for your development board.

So my first critique comes at this point where I must say this board is aimed strictly at hobbyists and first time Xilinx Users. Much more experienced developers might reach the pinnacle of the board’s performance in no time.

 

VIVADO Design Suite

Image 3: Vivado Design Suite

 

Like all development board, the ARTY S7 offers you an IDE and development platform. But unlike others, the design suite offered by Arty S7 is a powerful , cutting edge, technologically epic development platform called the Vivado Design Suite. Created and developed by Xilinx for their FPGAs, the Vivado offers FPGA development features which are unavailable on most other platforms.

Xilinx offers multiple versions of Vivado dependent on user requirements and usage. Including a free WebPack Version of Vivado, which surprising contains most of the development features offered by the paid version of the software.

The Vivado is quiet overwhelming to the first time user, but gradually turns out to be the most handiest tool that can be used by an engineer to develop, debug, troubleshoot ones whole project.

The Vivado offers an exceptional IP integration feature, which is a block design approach to creating your target system design. All of this far greater than any feature offered by any other development platform.

MICORBLAZE: This is a software based microcontroller IP integration core offered by Xilinx for usage in Vivado system design process. All components of board are added into the block design and integrated into using the Microblaze as the soft core.

Whats the downside? The Vivado comes in multiple versions. For easy understanding lets differentiate them as paid and free. The Webpack Version is completely free and should do for most project types and should do well enough for any hobby grade developer. But, if you are a research level developer, you are definitely gonna want the DSP system generator module as well. This feature is a paid add on to the Vivado and costs 995-1295$ depending on your license type. Although this is a major drawback, whether or not it affects the value of the Arty S7, is for anyone to say. As for me, Im going to pull down a single point from the board because it’s a feature available on the board but just not as easily accessible as the others. Well you might say, as a developer I must have a license but it seems something for enterprises and not individuals.

Narrowing down to a single drawback in the software section is definitely a great deal. After all I am still achieving it at no added costs. Value is still high for me.

 

PMOD

If Xilinix is the main reason you would buy the board, think again. Because Digilent are still the makers of this board and the reason for this board is Digilent’s own the - Pmod. These are individual module boards(eg. LCD, Bluetooth, driver, etc.) that you can hook on to your main Arty S7 and you interface them just like any other module. But Pmods are lot cooler than regular modules and once again Vivado does the trick of IP integration and Microblaze based block building. This is where your hobbygrade innovations and experimentation lies.

Suppose you don’t have any Pmods, you can just as easily interface with any Arduino or ChipKit module. This is exactly the kind of encouragement Digilent has for first time Xilinx users without scaring off any slow learners. Just joking. But on a serious note this is the perfect way to adapt to a new development environment and not have to abandon your previous platform. Instead, fuse them together to create something better.

Image 4: Digilent Pmod

 

PROs

  • - Value for Price
  • - Xilinx based system
  • - Spaciously designed component layout
  • - Great support from both Digilent as well Xilinx (This is not a joke. For any development platform to thrive and evolve, support is the only way. As for open source platforms, many developers post knowledge and insights which are usually lost to the new comer. But, in this case, Xilinx leaves out no single information documented. And Digilent has dedicated engineers to solve and debug every users problem)
  • - Perfect board with great specs with smart Pmod concept
  • - Elegant board design with quality components with an eye for good aesthetics.

CONs

  • Entry level board
  • Main FPGA is of Spartan series and most offerings by Xilinx does not come supported for the Spartan Family
  • Best suited for microcontroller applications over DSP ones.
  • Lesser support material compared to higher placed boards.
  • Considering I stay in India I have almost zero platforms offering to sell Pmod accessories.

 

CONCLUSION

The Digilent Arty S7 is a great development kit aimed at Hobbyists and hobby grade level developers. It is the perfect board for first time Xilinx users and can help you level up to a great platform for development methodologies and prototyping models the scientific way. This board is best applicable for embedded system students who are still unfamiliar with FPGAs.

The Vivado WebPack Edition is a wonderful platform for individual users who are not financed for the complete Vivado experience and should cover the best part of the features even for experienced developers.  Vivado Design Suite is the main design and programming workstation. It composes of vast and diverse design considerations at the user’s disposal.

 

FINAL COMMENTS

  1. If you are a hobbyists looking for the next board to buy, THIS IS IT! Without a doubt. All your innovative thinking can be shaped perfectly and realized with ease on this board.
  2. Once you have the board, collect as many Pmods as possible. These are very affordable and extremely easy to add to your projects.
  3. a learning base for yourself where you can gather information about Xilinx systems, Vivado, DSP design. Once you are here you are only going to reach higher and the possibilities are endless. This is just the beginning. And what a way to begin your FPGA development journey than the Arty S7
  4. This document is the very first of many to come. Follow this space and my personal blog for upcoming posts on projects using the Arty S7, mostly in audio applications.
  5. Main shoutout to Digilent. Good job! Also, Xilinx. Last but not the least element14 for this Roadtest and promoting a quality product.

 

DISCLAIMER

All images, links, diagrams used belong to their respective owners. This document is for educational purposes only.

 

 

PROJECT: S/PDIF Receiver Module

Board: ARTY S7

AIM: Create a digital audio receiver based on S/PDIF audio protocol using the Digilent ARTY S7 development.

 

TOOLS:

  1. Digilent Arty S7
  2. Xilinx Vivado Design Suite
  3. S/PDIF Audio Output
  4. Multimeter
  5. USB Oscilloscope

 

THEORY:

S/PDIF is an audio transmission protocol developed by Sony and Philips which is used in most digital audio equipment. It is popular in HiFi audio devices where multiple channels of audio is transmitted at high data rates and minimum losses.

S/PDIF is used alongside HDMI video transmission when audio and video are transmitted separately. Like any other digital transmission techniques, this digital audio interface uses 32-bit word formats to transmit samples at bit rates ranging from 32kHz to 192kHz.

All technical information required to understanding S/PDIF can be found in the link below,

http://www.hardwarebook.info/S/PDIF#Characteristics

 

AMBA AXI4

ARM Community have developed an interface methodology where multiple interface can be brought under a common platform and create interconnects with rapid fast development. Xilinx and ARM have worked together to create a very sophisticated and ultimately easy to use interfacing and IP interconnect.

The AXI4 interconnect covers as many interfaces as you could possibly think of. Ranging from Automotive to Media to DSP interfaces AXI4 can be used for multiple applications. Xilinx are also good enough to pin point every single interface a create a support manual for every one of them(all you need to do is Google: “‘x’ interface and AXI4 LogiCore IP”)

Below is the link to the support manual for the S/PDIF AXI4 LogiCore IP

https://www.xilinx.com/support/documentation/ip_documentation/spdif/v2_0/pg045_spdif.pdf

More information on AMBA AXI4 is available here,

https://www.xilinx.com/products/intellectual-property/axi.html#overview

 

NOTES BEFORE YOU BEGIN:

  1. Take care of your board – Any hardware interconnect should be tested multiple times for voltage and current status. Even the slightest bit of varying current/voltage condition could cause vital damage to your board. Unlike software, the hardware cannot be undone. Once bust is bust.
  2. Approach all projects software first. One all design and debugging is complete, make your way to hooking up the board to its respective I/Os.
  3. Vivado can be overwhelming at first. But absolutely any troubleshooting help can be found online. If none exists please post your queries on Digilent forums. Their hardworking engineers are kind enough to rectify all your issues.
  4. Don’t mess up your Workplace. A lot of troubleshooting can lead to unnecessary changes in the wrong area(like changing directory folders) which could lead to a lot of error in compilation.
  5. If you’ve reached Xilinx level of development all these rules must be very novice and you can skip this section.

 

Block Diagrams:

Vivado offers IP blocks(a library update might be required)which contains all Pmod blocks and Vivado offered design modules.

In this case we shall be using the S/PDIF IP block. It is based on the AXI4 interconnect methodology.

Vivado IP Block Creation for S/PDIF

Here’s where I hit the roadblock. Nowhere in any of Xilinx’s or Digilent’s Documentation have they mentioned SPDIF support for the Spartan- 7 Series. Although, Spartan is not mentioned in any the support section of any of the documents, 7 series FPGAs is mentioned in general. So Ill pause the project at this stage and do some further research. Alternatively, I can create a SPDIF to I2S converter circuit using a Cirrus Logic’s CS8422. More information here in the link below.

https://www.cirrus.com/products/cs8422/

TO BE CONTINUED…

 

Anonymous