Flashing/Upgrading the eMMC of Beaglebone Black (2018)

I am looking for instructions on how to upgrade my BeagleBone Black. Most of the instructions on the web are outdated and doesn't work. Here are the steps I did to upgrade my BBB:

1. Download the image from https://beagleboard.org/latest-images
2. Extract using 7-zip and you should be able to have a file with .img extension.
3. Write using Win32DiskImager.
4. As of this writing, there are additional step that needs to be done to enable the eMMC flasher on the image. You need to modify the uEnv.txt
1.  If you have Windows machine, use VirtualBox and load your favorite Linux distro (LUbuntu on my case)
2. Follow these steps extracted from Beagleboard.org:  To turn these images into eMMC flasher images, edit the /boot/uEnv.txt file on the Linux partition on the microSD card and remove the '#' on the line with 'cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh'. Enabling this will cause booting the microSD card to flash the eMMC. Images are no longer provided here for this to avoid people accidentally overwriting their eMMC flash.
5. Make sure that your BBB is turned off.
6. Plug in the SD card.
7. Press and Hold S2 button. (Don't let go!)
8. Plug in the power. 
9. Wait for the User LED to flash then about 4 to 5 seconds, release S2 button
10. Wait for around 10 to 20 seconds for the User LEDs to do "running LED lights". This is the signal that BBB is flashing.
11. Wait for user LEDs to turn off, this is the signal that BBB is finished flashing.
12. It will turn off at the end.
13. Remove power
14. Remove SD card.
15. Reapply power. 
16. Enjoy

Embedded C++ for MSP430 using IAR compiler

In my current project, I used Embedded C++ for MSP430 using IAR compiler. I re-created an existing assembly project and I was able to reduce the code size from 30KB down to 15KB. Yet, I have more features in my new Embedded C++ firmware. I am very careful with the C++ features that I used due to limited resources (processing power, RAM, FLASH size), the most expensive thing that I used is the virtual method which I essentially needed to implement strategy and template method design patterns.  I also used the Instantiator Based Programming Paradigm to eliminate unneeded build times (similar to C++ PIMPL) and to be able to adhere to a good programming principle: "Program to Interface, Not to implementation."

At the end of the project, the code size is small, the code is very expressive, code is unit-testable and the software architecture is very flexible due to application of object-oriented design patterns.

I am very impressed with the IAR C++ compiler.

Unit Testing Simple Linux Kernel Module

This morning, I am trying to learn Linux Kernel development from https://blog.sourcerer.io/writing-a-simple-linux-kernel-module-d9dc3762c234  Link  .

The examples are very good. However, I am looking for a way to do unit testing and I can't find any info on how to do this. I am a unit test advocate and I fully support unit testing. Why? Because system testing is expensive and from my experience, time-consuming.

I would like to unit test on Eclipse so that I could use Eclipse CDT and GDB's full power in terms of debugging.

Eclipse Oxygen.3 CDT Release (4.7.3)

With just a few #defines and #ifdefs, I was able to come up with a way to do simple unit tests using asserts. Nothing impressive actually, however the quick feedback of unit tests will be very helpful in getting good code coverage of testing.

I placed the source code demonstration here: Link

For now this will work, however I will be improving this and will be adding a proper unit testing framework.

My Less than $4 Faucet Temperature Monitor

This weekend, I was able to finish my temperature monitor. 

Faucet temperature monitor (I still need to tidy up the wiring LOL)

I just bought the following materials:
- Temperature display with thermocouple from Ebay ($1.50)
- Crayon box from Walmart ($1)
- Electrical tape

I used my Dremel tool to fit the crayon box into my faucet. All in all, I just spent less than $4.

Easy Arduino unit testing using Emulare and ArduinoUnit

I just uploaded a video on youtube on How to do Unit Testing on Arduino using Emulare and AndroidUnit. This is purely a simulator unit testing and doesn't require a board, which is great for unit testing.

Writing NFC app using Cordova for M24LR16 I2C RFID EEPROM - but...

I am in the process of creating an Android app using Cordova with phonegap-NFC plugin. I am interfacing with an RFID I2C EEPROM M24LR16 and my firmware is already ready and tested. I have the sample Android app of ST Microelectronics and the RFID EEPROM works and I can transfer and read data. But after building the Cordova app for 1 hour, it didn't work.

Digging into the documentation, phonegap-nfc doesn't support non-NDEF tags. Most folks are suggesting to modify the phonegap-NFC library for that purpose. It is my first time to work with NFC tag firmware and this is a very good learning experience. I don't know which path to go as of the moment, but I will try to modify the phonegap-NFC library. If it doesn't work out, I will develop the Android app using Android Studio.

Update:
I had just finished creating the Android app using Java (Android Studio). It works great with Non-NDEF NFC tags. :)

LORA: RF SX1278 Review

This weekend, I did a prototype project using LORA SX1278 for a 433MHz project. A friend of mine sent me two XL1278 module.

When I received the modules, I was so excited to test it. I have experience with TI CC1101/CC430 and NRF905 and I would like to do a comparison in terms of development time.

Upon reading the datasheet, everything is very straightforward. With the SX1278 datasheet's help, I was able to develop my C++ SX1278 driver and make it work with TI MSP430 FRAM microcontroller. Unlike, TI CC1101/CC430, I don't need any tool like SmartRF studio to get all the settings. I can just do a register computation for the frequency. Everything is straightforward with this LORA chip.

Since I don't have a spectrum analyzer, I used my $9 USB RTL-SDR (Software Defined Radio) to capture signals in the air. 

I used Spektrum (link) to see if there are any activities in the air if I transmit something. This Spektrum is pretty basic and it does it's job. I just hope that it would have a hold function like a normal spectrum analyzer (like holding a peak detection). But still, it is a very helpful tool. I don't need to buy a spectrum analyzer. :D

Spektrum Interface (not an actual picture from my experiment)

Continuing with my experiment, when there is no one transmitting, RSSI levels are at -137dBm. I tried transmitting something (I used Spreading Factor of 7 and I am transmitting 128 packets in one shot) and the receiver got a 128byte packet at -19dBm.  That is pretty impressive. I haven't done my Friis equation transmission equation analysis yet but looking at this data, I believe we can achieve very far range with this one.

This is a very good module. However, I may need to try some other antenna and I may need to design a quarter wave monopole antenna by hand before doing our range test.

-Jeff


(I don't own any of the picture, please see the link)
Image from: https://www.ebay.com/itm/433-LoRa-SX1278-Long-Range-RF-Wireless-Transceivr-Module-SX1276-5Km-For-Arduino-/322929644930
https://www.rtl-sdr.com/spektrum-new-rtl-sdr-spectrum-analyzer-software/

Textwrap: Impressive python module

I am currently reverse-engineering an audio analysis algorithm which computes for the statistical variance. I needed to get around 100,000 A/D data points from the MSP430's FRAM microcontroller so that I can inject it to my unit test. With that, IAR gives me a TI-TXT format.

example:
@10000
30 20 40 50
60 70 80 90

I needed to convert this to a C array so that I can place this inside my C++ code. Here are the steps I did:

1. I extracted all the data and placed them inside a list which is very easy to do using split, appending "0x" and using join. The output will be like this:
"0x30, 0x20, 0x60"  so on so forth

2. My problem with the above string is that it will take only one line of my C++ code which I feel won't look nice as I don't want to be scrolling horizontally as much as possible. I thought of creating a python algorithm to put newlines nicely without cutting a whole string like:
0x30, 0x20 ,0x
60, 0x70, 0x8
0, 0x20

Then I discovered python already covers it for me via textwrap module which I think is a smart algorithm. So now, I won't have any broken string and it will be printed nicely:

0x30, 0x20 ,0x60,
0x70, 0x80, 0x20

More information on how to use it here:  https://pymotw.com/2/textwrap/

Why TortoiseGit is so amazing

I had been using Git for a very long time and this is the best version control system that I ever used. In the past, I used centralized version control system: CVS, SVN, Visual SourceSafe, and TFS.  I heavily use TortoiseGit and I use git bash only if the feature isn't there on TortoiseGit . I also develop in Linux and I used Samba share drive or VirtualBox network share to be able to access my source code outside of Linux, so that I could use TortoiseGit on my codes.

Here is how Git changed my development style and quality of my code:

• Personal code review before committing - In TortoiseGit, it is very easy to see the diff of your current code change and the last commit via the included UI diff tool (I also use an external tool called WinMerge which is more faster). This diff will direct me to the exact place where I did my modification and this gives me a chance to have a second look if I accidentally forget or misplace something like reverting some debug compilation symbols that shouldn't be on production release.
  
  I noticed that git bash users (at least from the people that I know of) never do personal code reviews before committing and I think it is because it is not very straightforward to do so like in Tortoisegit. There was a project in my previous company where the developer unintentionally added a code which made the software release very unstable. They found out that some test snippets were included on the commit. A quick review of the software before commit will save tons of headaches.
• Stash - I love this feature. This helps me move through different git branches without committing my modified file and instead stash saving it and popping it out if I need to continue working on the modified files.
• Reviewing codes from other committers - It is very easy to review code from other committers via git log compare revision on TortoiseGit. This helps me review other developers work.
• Revert on TortoiseGit - whenever I do code review, and if I see that some of the codes needs to go back to its original state, I can just simple do a revert on the commit windows dialog box of TortoiseGit. 
• Very easy to merge codes
• Bisect - I used this only once. But bisect feature is very impressive.
• Distributed- being distributed is a very very very very very good thing. I commit often and sometimes, I don't have an internet connection. With this, I can commit anytime and once I have an internet connection, then that's the time I can push to the git server.

These are the things that I really like  in TortoiseGit which I had been using for many years. It is very simple and yet powerful.