Welcome

The Dallas .NET Micro User Group focuses on the .NET Micro Framework (NETMF) from Microsoft. The group meets on the 4th Wednesday of each month at Improving Enterprises and our meetings are free to attend. Please RSVP according to the monthly meeting announcement to assure plenty of food and drinks for everyone.

Newsletter

What is NETMF?

.NET Micro Framework (NETMF) is an open source platform that expands the power and versatility of .NET to the world of small embedded applications. Desktop programmers can harness their existing .NET knowledge base to bring complex embedded concepts to market on time (and under budget).  Embedded Developers can tap into the massive productivity gains that have been seen on the Desktop.

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User Group News

Other News

Friday, August 28, 2015 2:25:28 AM
After a long await, the GHI boot loader is now available for G400 family of products! Developers can now easily update the G400 SoMs without the need for the SAM-BA tools. The whole update process is simple and can be done using FEZ Config. FEZ Raptor owners will find this loader useful as the LDR buttons will now function properly.

The loader has been well tested but it is still in beta. It is not recommended to ship on products just quite yet, but we encourage everyone to try it and provide us with feedback, both good and bad.

Deploying and using the loader is documented in the support document located here.

Support Document: https://www.ghielectronics.com/docs/336/installing-the-g400-bootloader
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Wednesday, August 26, 2015 4:51:16 AM
The Arduino form-factor has been very popular on many products and now it is available on the all new FEZ Cobra III. Today, developers have three options, the low cost FEZ Lemur, the versatile FEZ Panda III or the high-end and parallel-display-capable FEZ Cobra III.

Based on the G120 SoM, the FEZ Cobra III has a 120Mhz processor with built-in networking and graphics support that will provide you with enough horsepower and memory for all of your IoT projects! Besides the standard Arduino-style headers, the FEZ Cobra III comes with two additional headers, providing access to 40 pins that cover everything from GPIO and Analog, to PWM and SPI.

The 40 pin header on the FEZ Cobra III follows a new defined standard created by GHI Electronics, called GXP (General Expansion Port). This allows everyone to create display boards with a standardized connection. For example, we have created a Gadgeteer GXP breakout board. This board allows any Gadgeteer display to be connected to the FEZ Cobra III, please see the image below. While we are still experimenting with the breakout board and other ideas, none are available just yet. Of course, you can connect any display using wires today.



One last note about the GXP header (the display port basically). The 40 pin 0.1" header is compatible with IDE hard drive cables. Those cables can be found at many computer stores. These cables can be used to extend the connection between the FEZ Cobra III and the display.


The latest SDK supports the G120 SoM and can be used with the FEZ Cobra III; however, the pinout enumeration (the pins class) is not in the SDK just yet. Fear not, the class is provided separately until it is available in the next SDK. You can find this class in the FEZ Cobra III Developer's guide.

FEZ Cobra III: https://www.ghielectronics.com/catalog/product/540
FEZ Cobra III Developers' Guide: https://www.ghielectronics.com/docs/335/fez-cobra-iii-developers-guide
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Monday, August 17, 2015 1:46:40 AM
The Raspberry Pi is an amazing little piece of hardware. Essentially, a $35 PC. However, when it comes to the Internet of Things and connecting sensors and control modules, it falls a little short. Its male pins are not easy to wire, the pins are not 5V tolerant, there are no PWM outputs and there are no Analog inputs. This is true for both the original Raspberry Pi and Raspberry Pi 2.

Thanks to the all new FEZ Utility, connecting all kinds of sensors and devices couldn't be easier!

Key Features:
  1. All Raspberry Pi's original pins are exposed (and labeled) on female headers.
  2. 13 5V-tolerant GPIO pins.
  3. 14 PWM outputs.
  4. 8 Analog Inputs.
  5. 4 LEDs, 2 of them are PWM ready for dimming.

The FEZ Utility is compatible with Raspberry PI 2 model B and Raspberry PI 1 model B+. Complete drivers are provided for Windows 10 but Linux can work as well.

If you are planning on connecting anything to your Raspberry Pi besides a USB cable then you must own the very versatile FEZ Utility HAT.

FEZ Utility: https://www.ghielectronics.com/catalog/product/545
Raspberry Pi HATs: https://www.ghielectronics.com/catalog/category/538
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Monday, August 17, 2015 12:38:03 AM
We come to you today with very good news but let us give you some history, maybe you will learn something as well.

Over a year ago, we were contacted by one of our important customers saying that some EMX modules are failing at high temperatures, around 70 degree Celsius (158 degree Fahrenheit). They have used EMX for years with no problems so something must have changed. We started looking into lot numbers and manufacturing dates. It looked all random but we were certain that this problem did not exist before. We could not find a definite date but a few things had changed. The SDRAM we used was discontinued and we replaced it with a compatible version, we had moved to a new building, we have processors with new manufacturing dates and we changed the stencil printer with a high end (and very expensive) solder jet printer.

The first candidate was the solder jet printer. This is a new technology that allows companies to print solder right onto the raw circuits, instead of using stencils. While, it costs hundreds of thousands of dollars, it may not be perfect. There was also a concern that the reflow process was not tuned right to the type of solder we use with the solder jet printer. So, a few samples were shipped to one of our partners who own a X-ray machine. They found no problems in the soldering quality. Ok good... it is not the machines!

We then started looking into the SDRAM but then we learned that some modules do not fail ever and they use the exact same SDRAM. Still, we got right to the SDRAM datasheet and triple checked everything. No problems were found there.

Now we are sure it is static issue, right? No wrong. An independent company was hired to test our facility for static and they found no issues.

So it has to be a bad batch of processors right? We quickly got a hold of NXP and started working with them on investigating the issue. According to them it was a moisture issue and the chips needed to be baked! This was the worst answer they could have given us because we are now sure this was not the problem and they simply pulled this random answer to get us off their back! We spent weeks, and maybe months, baking and trying different things. We have gone so far thinking the problem is related to an error in our manufacturing.

At this point, we have spent months upon months of work, with literally thousands of dollars just running down the drain. But we knew, nothing would stop our engineers from finding the mysterious issue.

The last resort was in testing the individual components on the EMX module, CPU, flash, RAM and peripherals. The difficult part was EMX will only fail if it was put in a heat chamber and let run for a few hours. You can imagine the frustration there. We write a test program, load on EMX, put EMX in the oven, and wait for few hours just to see if the individual test would fail or not. For that, we had few EMX modules cycling through with different tests.

We finally found the issue! One of the timing parameters was setting the clocks right on the edge of accepted levels. We slowed things down very slightly and EMX never failed again.

But who's fault is this? And why it took so long and cost so much to solve? We want to say it is simply bad luck. The same values worked on thousands of EMX modules running in hundreds of products around the world for about 7 years! Then one day, something on the CPU, in the SDRAM, in the PCB impedance or a combination of those caused few to fail at extreme temperatures.

We completely agree with our customer's frustration over this issue. There was unfortunately no magical answer. Only hard work and dedication is what solved this mystery. Please accept our apologies for what happened and we hope that everyone understands that this was beyond anyone's control.

The fix is available in the current beta release. Thank you for continuing to believe in GHI Electronics and standing behind our products.

SDK: https://www.ghielectronics.com/support/netmf/sdk/37/ghi-electronics-netmf-sdk-2015-r1-pre-release-4
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Thursday, August 6, 2015 4:54:37 AM
If you are wondering whether or not the FEZ HAT can be used with Linux then wonder no more! @Josh recently tackled the FEZ HAT and locked himself away until he got it working with Linux on the Raspberry Pi. Don't believe me? Then check out his blog post and video!


http://youtu.be/koe51uSbdjI


FEZ HAT: https://www.ghielectronics.com/catalog/product/500
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