<div class="entry-content">
    <div class="jetpack-video-wrapper"><span class="embed-youtube" style="text-align:center; display: block;"><iframe src="https://www.youtube.com/embed/fFI33f4TejM" class="youtube-player" width="740" height="416.418" frameborder="0" allowfullscreen></iframe></span>
    </div>
    <div class="blog-content">
Ken Burns has published 7 hardware projects on Kickstarter. He explains how it works.
    </div>
    
    <div class="blog-content-links">
        <div>
            Links:
        </div>
        <ul class="links-list">
            <li class="links-list-item"><a href="https://tinycircuits.com/">Ken's company TinyCircuits</a></li>
            <li class="links-list-item"><a href="https://fedevel.com/courses">FEDEVEL Online courses</a></li>
        </ul>
    </div>  
</div>

Can You Make Money on Kickstarter HW Projects?

<div class="entry-content">
    <div class="jetpack-video-wrapper"><span class="embed-youtube" style="text-align:center; display: block;"><iframe src="https://www.youtube.com/embed/2oA4X3OTz0M" class="youtube-player" width="740" height="416.418" frameborder="0" allowfullscreen></iframe></span>
    </div>
    <div class="blog-content">
Interesting experiments and examples to help you to understand ground layout in PCB. Explained by Hans Rosenberg
    </div>


    <div class="blog-content-chapters">
        <div>
            Chapters:
        </div>
        <ul class="chapters-list">
            <li class="chapters-list-item"><span class="chapters-time">00:00</span><span class="chapters-text">What is this video about</span></li>
            <li class="chapters-list-item"><span class="chapters-time">00:19</span><span class="chapters-text">Currents flow under track</span></li>
            <li class="chapters-list-item"><span class="chapters-time">03:10</span><span class="chapters-text">What happen when you are making a board</span></li>
            <li class="chapters-list-item"><span class="chapters-time">08:37</span><span class="chapters-text">Where currents flow</span></li>
            <li class="chapters-list-item"><span class="chapters-time">14:01</span><span class="chapters-text">Experiment: Cut under track</span></li>
            <li class="chapters-list-item"><span class="chapters-time">19:51</span><span class="chapters-text">Floating copper fill</span></li>
            <li class="chapters-list-item"><span class="chapters-time">23:15</span><span class="chapters-text">Grounded copper fill</span></li>
            <li class="chapters-list-item"><span class="chapters-time">27:04</span><span class="chapters-text">Experiment: Filter</span></li>
            <li class="chapters-list-item"><span class="chapters-time">35:05</span><span class="chapters-text">2 Layer vs. 4 Layer</span></li>
            <li class="chapters-list-item"><span class="chapters-time">44:00</span><span class="chapters-text">3 rules to prevent ground problems</span></li>
            <li class="chapters-list-item"><span class="chapters-time">46:05</span><span class="chapters-text">Example: Ground plane</span></li>
            <li class="chapters-list-item"><span class="chapters-time">49:52</span><span class="chapters-text">Example: 1 VIA per GND pin</span></li>
            <li class="chapters-list-item"><span class="chapters-time">54:46</span><span class="chapters-text">Example: Gap in GND plane</span></li>
            <li class="chapters-list-item"><span class="chapters-time">1:02:00</span><span class="chapters-text">Example: FPGA board redesign</span></li>
            <li class="chapters-list-item"><span class="chapters-time">1:05:16</span><span class="chapters-text">Star grounding</span></li>
            <li class="chapters-list-item"><span class="chapters-time">1:07:39</span><span class="chapters-text">Multiple ground planes</span></li>
            <li class="chapters-list-item"><span class="chapters-time">1:14:30</span><span class="chapters-text">Example: Digital and Analog on one board</span></li>
            <li class="chapters-list-item"><span class="chapters-time">1:16:40</span><span class="chapters-text">About Hans</span></li>
    </div>
    
    <div class="blog-content-links">
        <div>
            Links:
        </div>
        <ul class="links-list">
            <li class="links-list-item"><a href="https://www.youtube.com/@HansRosenberg74">Hans´ YouTube</a></li>
            <li class="links-list-item"><a href="https://www.hans-rosenberg.com/">Hans´ website</a></li>
            <li class="links-list-item"><a href="https://fedevel.com/courses">FEDEVEL Online courses</a></li>
        </ul>
    </div>  
</div>

Examples of BAD Ground in PCB Layout And How to Fix It

<div class="entry-content">
    <div class="jetpack-video-wrapper"><span class="embed-youtube" style="text-align:center; display: block;"><iframe src="https://www.youtube.com/embed/X-qubBLJDD8" class="youtube-player" width="740" height="416.418" frameborder="0" allowfullscreen></iframe></span>
    </div>
    <div class="blog-content">
What will happen if you don't have enough GND pins on your connector?
    </div>
    
    <div class="blog-content-links">
        <div>
            Links:
        </div>
        <ul class="links-list">
            <li class="links-list-item"><a href="https://www.colorado.edu/faculty/bogatin/">About Eric</a></li>
            <li class="links-list-item"><a href="https://fedevel.com/courses">FEDEVEL Online courses</a></li>
        </ul>
    </div>  
</div>

Do You Design Connector Pinout Correctly? | Eric Bogatin

<div class="entry-content">
    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/69fdb-imx_rex6_module_top_hr.jpg" alt="imx rex6 module top HR" />
    </div>

    <div class="blog-content">
        <b>Here are the real numbers from designing the iMX6 Rex prototype</b><br><br>
        <i>*Note:These numbers don’t include 50 hours of work spent by a Senior engineer to check the work.</i>
    </div>

    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/097a5-imx6-rex-timesheet-total.jpg" alt="iMX6 Rex Timesheet - Total" />
    </div>    
    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/18c55-imx6-rex-timesheet-schematic.jpg" alt="iMX6 Rex Timesheet - Schematic" />
    </div>    
    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/735c5-imx6-rex-timesheet-library.jpg" alt="iMX6 Rex Timesheet - Library" />
    </div>    
    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/650f3-imx6-rex-timesheet-pcb.jpg" alt="iMX6 Rex Timesheet - PCB" />
    </div>

    <div class="blog-content">
        <b>Detailed description</b>
        <ol class="content-list">
            <li class="content-list-item"><span class="content-text">Specification, comparison with similar project, finding reference design [Duration: 03h 49m]</span></li>
            <li class="content-list-item"><span class="content-text">Working on schematic [Duration: 01h 03m]</span></li>
            <li class="content-list-item"><span class="content-text">Replacing pin designators for iMX processor [Duration: 05h 09m]/span></li>
            <li class="content-list-item"><span class="content-text">Changing and creating schematic [Duration: 21h 54m]</span></li>
            <li class="content-list-item"><span class="content-text">Power management, power up sequencing [Duration: 11h 28m]</span></li>
            <li class="content-list-item"><span class="content-text">Updating ports and nets [Duration: 07h 13m]</span></li>
            <li class="content-list-item"><span class="content-text">Drawing block diagram [Duration: 01h 15m]</span></li>
            <li class="content-list-item"><span class="content-text">Working on connector [Duration: 03h 48m]</span></li>
            <li class="content-list-item"><span class="content-text">Changing Ethernet PHY interface [Duration: 02h 26m]</span></li>
            <li class="content-list-item"><span class="content-text">Schematic preliminary checking [Duration: 00h 57m]</span></li>
            <li class="content-list-item"><span class="content-text">Updating and creating components [Duration: 05h 15m]</span></li>
            <li class="content-list-item"><span class="content-text">Updating and creating footprints [Duration: 04h 33m]</span></li>
            <li class="content-list-item"><span class="content-text">Fixing compiled errors and warning [Duration: 01h 48m]</span></li>
            <li class="content-list-item"><span class="content-text">Schematic checking [Duration: 00h 23m]</span></li>
            <li class="content-list-item"><span class="content-text">Preliminary Component placement [Duration: 10h 49m]</span></li>
            <li class="content-list-item"><span class="content-text">Finding handsome 3D model of component [Duration: 02h 13m]</span></li>
            <li class="content-list-item"><span class="content-text">RF: Checking schematic [Duration: 00h 35m]</span></li>
            <li class="content-list-item"><span class="content-text">Updating schematic after preliminary checking [Duration: 05h 01m]</span></li>
            <li class="content-list-item"><span class="content-text">Schematic symbol checking [Duration: 15h 15m]</span></li>
            <li class="content-list-item"><span class="content-text">Schematic browsing [Duration: 31h 56m]</span></li>
            <li class="content-list-item"><span class="content-text">Ordering components [Duration: 03h 45m]</span></li>
            <li class="content-list-item"><span class="content-text">Footprint checking [Duration: 06h 50m]</span></li>
            <li class="content-list-item"><span class="content-text">Component placement V2 [Duration: 02h 27m]</span></li>
            <li class="content-list-item"><span class="content-text">Preliminary layout [Duration: 07h 39m]</span></li>
            <li class="content-list-item"><span class="content-text">Processor power fanout and preliminary layout [Duration: 17h 00m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory data signal fanout, first layout [Duration: 19h 23m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory address signal fanout, first layout [Duration: 09h 32m]</span></li>
            <li class="content-list-item"><span class="content-text">Ethernet PHY replacement and connection [Duration: 08h 59m]</span></li>
            <li class="content-list-item"><span class="content-text">Processor signal fanout – processor, connector J1 [Duration: 18h 21m]</span></li>
            <li class="content-list-item"><span class="content-text">Processor signal fanout – processor, connector J2 [Duration: 23h 16m]</span></li>
            <li class="content-list-item"><span class="content-text">Providing changes from RF checking [Duration: 15h 11m]</span></li>
            <li class="content-list-item"><span class="content-text">Finishing preliminary layout [Duration: 02h 42m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory length matching – data [Duration: 38h 00m]</span></li>
            <li class="content-list-item"><span class="content-text">Working on mechanical layers [Duration: 02h 56m]</span></li>
            <li class="content-list-item"><span class="content-text">Optimizing layout [Duration: 28h 21m]</span></li>
            <li class="content-list-item"><span class="content-text">Checking conflict in IOMux [Duration: 02h 45m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory length matching – address [Duration: 27h 23m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory length matching – clock [Duration: 04h 02m]</span></li>
            <li class="content-list-item"><span class="content-text">Optimizing layout – inner layers [Duration: 26h 56m]</span></li>
            <li class="content-list-item"><span class="content-text">Memory layout checking [Duration: 15h 51m]</span></li>
            <li class="content-list-item"><span class="content-text">Optimizing layout – top & bottom [Duration: 08h 37m]</span></li>
            <li class="content-list-item"><span class="content-text">Manufacturing layers optimizing [Duration: 03h 01m]</span></li>
            <li class="content-list-item"><span class="content-text">Releasing board [Duration: 06h 08m]</span></li>
            <li class="content-list-item"><span class="content-text">Ordered components checking [Duration: 02h 13m]</span></li>
        </ol>
    </div>
    <div class="blog-content-text">
        I need to say, Martin had no previous experience with advanced electronic design. He started working on this project in April 2013 and we have got the prototype boards in October 2013. He graduated at University in Jun 2013. It took 7 months to get the board.<br><br>

        You can easily compare the numbers with a very similar design which I have done some time ago: <a href="http://www.fedevel.com/blog/do-you-know-how-long-schematic-design-and-pcb-layout-take/">How long Schematic design and PCB layout take – Check here</a><br><br>
        
        When you compare:
        <ul class="content-list">
            <li class="content-list-item"><span class="content-text">Schematic design 95 hours (<a href="http://www.fedevel.com/blog/ti-c6a816x-computer-on-module-design/">TI C6 board</a>) vs 96.35 hours (<a href="http://www.imx6rex.com/">IMX6</a>)</span></li>
            <li class="content-list-item"><span class="content-text">Libraries 50 hours vs 45.22 hours</span></li>
            <li class="content-list-item"><span class="content-text">PCB 215 hours vs 296.57 hours</li>
        </ul>

        These numbers are very similar, so you can easily predict how long it will take you to design this kind of board. And … <b>“It is very interesting to see, that Junior Engineers can work very well and quite efficiently. This is the proof.”</b>
    </div>

    <div class="blog-content-text">
        How is it possible, that an inexperienced engineer could design this kind of board? He is really good. Martin is also taking a part in our new training program which we are developing at FEDEVEL Academy. The program will help everyone interested in hardware design to get a real experience from real projects. We hope, this will help students & young engineers to find a job or to get a better paid job. If you have a company, the FEDEVEL Academy training will help you to prepare your junior & young engineers to start working on your projects as soon as possible.
    </div>

    <div class="blog-content-text">
        <b>Conclusion</b><br>
        A good junior hardware design engineer can work very effectively.
    </div>



    <div class="blog-content-links">
        <div>
            Links:
        </div>
        <ul class="links-list">
            <li class="links-list-item"><a href="http://www.fedevel.com/blog/do-you-know-how-long-schematic-design-and-pcb-layout-take/">How long Schematic design and PCB layout take – Check here</a></li>
            <li class="links-list-item"><a href="http://www.fedevel.com/blog/ti-c6a816x-computer-on-module-design/">TI C6 board</a></li>
            <li class="links-list-item"><a href="http://www.imx6rex.com/">IMX6</a></li>
    </div>
</div>

How long it takes a Junior Engineer to design an Advanced board?

<div class="entry-content">
    <div class="blog-content-img-wrapper">
        <img src="https://assets.fedevel.com/blog/2019/10/ac6c6-running-memory-tests.jpg" alt="running memory tests" />
    </div>
    <div class="blog-content">
        Every hardware design engineer wants to be sure that the DDR3 memory interface is working correctly. Here are some real examples of DDR3 memory testing from our open source <a href="http://www.imx6rex.com/">iMX6 Rex project</a>.
    </div>
    <div class="blog-content">
        <h2 class="blog-content-heading">Which of the memory tests?</h2>
        There are a lot of memory tests available. For this project I used three:
        <ul class="content-list">
            <li class="content-list-item"><span class="content-text">the standard ubuntu <a href="http://manpages.ubuntu.com/manpages/hardy/man8/memtester.8.html">memtester</a></span></li>
            <li class="content-list-item"><span class="content-text"><a href="https://code.google.com/p/stressapptest/">stressapptest</a> (according to the website “… It has been used at Google for some time …”)</span></li>
            <li class="content-list-item"><span class="content-text">the Freescale memory test included in the <a href="https://community.freescale.com/docs/DOC-96412">i.MX6 DDR Stress Test Tool</a> (the same tool which is used also for calibration)</span></li>
        </ul><br>
        I recommend the stressapptest.
    </div>
    
    <div class="blog-content">
        <h2 class="blog-content-heading">What did I test?</h2>
        I was curious, so I have done tests of “uncalibrated” and “calibrated” board. “Uncalibrated” board was using the unchanged settings of DDR3 memory registers (the same values as used on the reference board), “calibrated” board was using the proper register values which I have got after the DDR3 calibration.
    </div>

    <div class="blog-content">
        <h2 class="blog-content-heading">The results</h2>
        Initially, I was running the “uncalibrated” board. The <b>memtester</b> software was running on this board for a week with <b>no errors.</b> When I used the <b>stressapptest</b> – the board always <b>failed within one hour</b>. This is how the failing looked: <br><br>

        <i>“Uncalibrated DDR3” – Examples of failing memory test</i>
    </div>
    <div class="blog-content-code">
        <code>Log: Seconds remaining: 4350<br>
        Report Error: miscompare : DIMM Unknown : 1 : 1658s<br>
        Hardware Error: miscompare on CPU 0(0xF) at 0x2be72978(0x4ca1997a:DIMM Unknown): read:0xff7fffffffffffff, reread:0xff7fffffffffffff expected:0xff7fffffff7fffff<br><br>
        
        Log: Seconds remaining: 4840<br>
        Report Error: miscompare : DIMM Unknown : 1 : 1169s<br>
        Hardware Error: miscompare on CPU 0(0xF) at 0x2bd89a78(0x4e3c7a7a:DIMM Unknown): read:0xff7fffffffffffff, reread:0xff7fffffffffffff expected:0xff7fffffff7fffff<br><br>
          
        Log: Seconds remaining: 3100<br>
        Report Error: miscompare : DIMM Unknown : 1 : 2904s<br>
        Hardware Error: miscompare on CPU 0(0xF) at 0x38171e78(0x27dcbe7a:DIMM Unknown): read:0xff7fffffffffffff, reread:0xff7fffffffffffff expected:0xff7fffffff7fffff<br><br>
        
        Log: Seconds remaining: 5550<br>
        Report Error: miscompare : DIMM Unknown : 1 : 455s<br>
        Hardware Error: miscompare on CPU 0(0xF) at 0x2fced578(0x200f157a:DIMM Unknown): read:0xff7fffffffffffff, reread:0xff7fffffffffffff expected:0xff7fffffff7fffff</code>
    </div> 
    <div class="blog-content-text">
        After applying the correct DDR3 settings from the DDR3 calibration (adding the correct register settings into uBoot), the same board was running perfectly.<br><br>

        <i>“Calibrated DDR3” – running perfectly over night (the same board was failing before)</i>
    </div>
    <div class="blog-content-code">
        <code>Stats: Found 0 hardware incidents<br>
        Stats: Completed: 32146856.00M in 0.00s infMB/s, with 0 hardware incidents, 0 errors<br>
        Stats: Memory Copy: 32146856.00M at -24559.40MB/s<br>
        Stats: File Copy: 0.00M at 0.00MB/s<br>
        Stats: Net Copy: 0.00M at 0.00MB/s<br>
        Stats: Data Check: 0.00M at 0.00MB/s<br>
        Stats: Invert Data: 0.00M at 0.00MB/s<br> Stats: Disk: 0.00M at 0.00MB/s<br><br>
        
        Status: PASS - please verify no corrected errors</code>
    </div> 
    <div class="blog-content-text">
        Here is the command line I used for the basic testing:
    </div>
    <div class="blog-content-code">
        <code># stressapptest -s 3600 -M 256 -m 4 -C 4 -W</code>
    </div> 
    <div class="blog-content-text">
        If you would like to install the strassapptest on your own ARM board, <a href="http://www.imx6rex.com/software/stress-testing-stressapptest/">check out here.</a>
    </div>

    <div class="blog-content">
        <h2 class="blog-content-heading">Be aware</h2>
        Be aware, that you need to test more boards. I have tested couple of “uncalibrated” boards and not all of them failed the stressapptest. When you are happy with the results (all your boards must always pass the test), take couple of boards (at least 5) and run the same tests in an environmental chamber (from -40C up to the maximum temperature … 60/70/80C ..). All the “calibrated” boards must pass your testing.<br><br>

        Happy testing!
    </div>
    
    <div class="blog-content-links">
        <div>
            Links:
        </div>
        <ul class="links-list">
            <li class="links-list-item"><a href="http://www.imx6rex.com/">iMX6 Rex project</a></li>
            <li class="links-list-item"><a href="http://manpages.ubuntu.com/manpages/hardy/man8/memtester.8.html">Memtester</a></li>
            <li class="links-list-item"><a href="https://code.google.com/p/stressapptest/">Stressapptest</a></li>
            <li class="links-list-item"><a href="https://community.freescale.com/docs/DOC-96412">i.MX6 DDR Stress Test Tool</a></li>
            <li class="links-list-item"><a href="http://www.imx6rex.com/software/stress-testing-stressapptest/">iMX6 Rex - Stress tests</a></li>
        </ul>
    </div>
</div>


ARM DDR3 Memory testing

<div class="entry-content">
    <div class="blog-content">
        Everyone interested to have the slides from my presentation at the <a href="http://www.hackerdojo.com/">Hacker Dojo</a> in Silicon Valley, can download them here:<br><br>

        <a href="https://assets.fedevel.com/blog/downloads/Learn-to-Design-your-own-ARM-Boards-FEDEVEL.pdf" target="_blank">Download “Learn to Design your own OS booting ARM board” ppt file here</a>.
    </div>
    <div class="blog-content">
        <h2 class="blog-content-heading">Content: Part 1</h2>
        <ul class="content-list">
            <li class="content-list-item"><span class="content-text">Projects</span></li>
            <li class="content-list-item"><span class="content-text">What is important when starting a newARM design?</span></li>
            <li class="content-list-item"><span class="content-text">Selecting components for a board running an operating system</span></li>
            <li class="content-list-item"><span class="content-text">Tips for ARM Schematic design</span></li>
            <li class="content-list-item"><span class="content-text">PCB Stackup & Impedances</span></li>
            <li class="content-list-item"><span class="content-text">PCB Stackup & Impedances (Calculation)</span></li>
            <li class="content-list-item"><span class="content-text">The most common High Speed Design Rules</span></li>
            <li class="content-list-item"><span class="content-text">iMX6 DDR3 layout and length matching</span></li>
            <li class="content-list-item"><span class="content-text">T-branch vs. Fly-by</span></li>
            <li class="content-list-item"><span class="content-text">DDR3 read / write leveling</span></li>
            <li class="content-list-item"><span class="content-text">Memory length matching spreadsheet</span></li>
            <li class="content-list-item"><span class="content-text">Memory Layout example in Altium</span></li>
        </ul>
    </div>
    <div class="blog-content">
        <h2 class="blog-content-heading">Content: Part 2</h2>
        <ul class="content-list">
            <li class="content-list-item"><span class="content-text">How does ARM boots?</span></li>
            <li class="content-list-item"><span class="content-text">How to setup a machine for ARM code compilation</span></li>
            <li class="content-list-item"><span class="content-text">How to compile bootloader</span></li>
            <li class="content-list-item"><span class="content-text">How to modify bootloader</span></li>
            <li class="content-list-item"><span class="content-text">Bootloader compilation example</span></li>
            <li class="content-list-item"><span class="content-text">Bootloader commands</span></li>
            <li class="content-list-item"><span class="content-text">How to build a Linux Kernel</span></li>
            <li class="content-list-item"><span class="content-text">How to prepare a File system</span></li>
            <li class="content-list-item"><span class="content-text">Steps to bring your board to life</span></li>
            <li class="content-list-item"><span class="content-text">DDR3 calibration</span></li>
            <li class="content-list-item"><span class="content-text">Board testing and HW verification</span></li>
            <li class="content-list-item"><span class="content-text">Thank you</span></li>
        </ul>
    </div>

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Learn to Design your own OS booting ARM board

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