Wednesday, July 7, 2021

Wednesday, April 7, 2021

Sunday, April 5, 2020

Using Orange Pi

Orange Pi is a cheap alternative to Raspberry. They can be bought at their online store Shenzhen Xunlong at Aliexpress. There are many Orange Pi models. For example, Orange Pi One costs only ~USD 10. Another model called Orange Pi PC Plus even has 8 GB eMMC onboard and costs ~USD 25 only.


Figure. Orange Pi One





Saturday, March 28, 2020

Tesseract OCR with C++, OpenCV, and wxWidgets

Tesseract is a free optical character recognition software and it is considered one of the most accurate open-source OCR engines [1].


Getting Started with FRDM-K64F

To use FRDM-K64F with the latest MCUXpresso IDE, you need to update the firmware for its debugger. It is similar to FRDM-K82F where the details can be seen at the following post.

http://cool-emerald.blogspot.com/2020/01/getting-started-with-frdm-k82f.html

There are only a few minor difference between FRDM-K64F and FRDM-K82F to get started. Therefore, I will only list some major points here.


Figure. FRDM-K64F board


Original OpenSDA appears as MBED drive. And it is not working with MCUXpresso. To update the firmware for its debugger,
  • Disable 'Windows storage services' ( https://os.mbed.com/blog/entry/DAPLink-bootloader-update/)
  • Hold reset button and connect the device to a USB port. It should now appear as a drive called BOOTLOADER
  • Drag and drop bootloader ‘0244_k20dx_bootloader_update_0x5000.bin’ into the drive.
  • Remove and reconnect without holding reset. Board shows as ‘MAINTANCE’.
  • Drag and drop Segger jLink OpenSDA for board specific firmware for K64F (‘02_OpenSDA_FRDM-K64F.bin’) which is available at https://www.segger.com/downloads/jlink#JLinkOpenSDABoardSpecificFirmwares
  • Remove and reconnect without holding reset button. It now appears as ‘FRDM-K64FJ’
  • To use JLink , open cmd and enter

    > cd "C:\Program Files (x86)\SEGGER\JLink"
    > JLink.exe -speed auto -device 'MK64FN1M0xxx12' -if SWD
    


  • At the JLink prompt

    J-Link> r
    J-Link> erase
    J-Link> q
    


  • After that, it should be OK to use MCUXpresso

Tuesday, March 24, 2020

ADS1115 ADC

ADS1115 is a precision, low power, 16 bit 860 SPS I2C analog to digital converter (ADC). It has internal reference, oscillator, and programmable comparator. ADS1115 modules are readily available at online markets like AliExpress and Adafruit



Friday, February 28, 2020

Working with JSON in C++

In this article, using JsonCpp library and wxJson library to work with JSON (JavaScript Object Notation) in C++ is discussed.


JsonCpp

A convenient way to use JsonCpp is adding its amalgamated source. At first, get the source from the official repository,

https://github.com/open-source-parsers/jsoncpp,

by entering the following command.

$ git clone https://github.com/open-source-parsers/jsoncpp.git