logging the data from USART

[cjackie]

We need to log the data from the USART. The data need to be collected for analysis of the sensors, motors and the quadcopter. The data should be readable. Something like output the data to STDOUT will be ideal,

[kbumsik]

Are we already using functions like TM_USART_Puts()?

[cjackie]

yea. But it gets send to the GUI interface terminal, right? I can see the data on that GUI interface, but Plain text will be better. It's easier to use other programming language to do some analysis, like figure out mean, variance(bias) and so on. If it gets send to STDOUT in real time, then, we can do alot of analysis real time. I saw something like StartLog on the GUI, so maybe that will work(logging data as plain text somewhere).

[cjackie]

By the way, the idea of using another computing platform doing high level optimization will be interesting(doing intense calculation). like mounting raspberry PI on the board and then interface with it using SPI or something. It will relieve huge burden on the microcontroller, as well as me for programming it(doing high level math operation in c is nightmare. lol.....)

[kbumsik]

• Yeah, mounting raspberry Pi and communicating between the two is my the next step after just making to see the quadcopter flying. I am also studying how to build APIs for Linux right now. But the nucleo board itself should do the calibration and track the motion like what you are doing. And I believe our microcontroller has enough performance.
• Raspberry Pi can be used for additional application for the drone visual computing, adding GPS or adding extra sensors for object detection like the video you showed be a few days ago but it is not a good idea for calculation unit for the drone engine itself. I know you are having problem implementing your theory so you could possibly implement it on the Raspberry Pi first for the developing speed. But communication device like USART and SPI is far much slower the computation power of NUCLEO microcontroller (they are bottlenecks!). Sending and receiving too much data between the two devices would rather drag down the overall performance.
• Do you mean STDOUT is the standard output library of C language? Using printf() function and using sprinf() and then TM_SUART_Puts() technically have no difference in embedded system. The only difference is the length of code: 1 line for only prinf() vs 2 lines for sprinf() and TM_USART_Puts().
• And hey, sprintf() is also a part of standard output library. sprintf() makes a formatted string object(the object is the first argument of the function), and printf() makes the same formatted object(but the string object's name is STDOUT for prinf) and then directly sends the STDOUT object to predefined target, cmd.exe shell for Windows, terminal shell for Linux, and USART or SPI devices for the microcontrollers, depending on our implementation.
• For more information: in case of reading strings, scanf() function reads the string from STDIN object. sscanf() function reads a string from the object we specify. (look at my example code here: https://github.com/kbumsik/Quadcopter-Flight-Controller/blob/master/project_components/motor/src/main.c#L86-L89)
• My explanation on STDOUT and STDIN objects is not 100% right, they are actually FILE objects containing string buffers. But I hope it would help you to understand.
• ANYWAY, the good really good news is, it is quite easy to make the program you want. Okay, what the TM_USART_Puts() function does is sending messages using USART to Serial ports (COM port in Windows, TTY port in Linux.) So what the GUI terminal program we are using is, just catching messages from serial port or send messages . Windows, Linux and many other programs provide simple APIs to catch serial port messages.
• So I can make a JAVA program that creates .txt file right this weekend (tomorrow is the final exam lol) if you want. I will use this example: http://www.java-samples.com/showtutorial.php?tutorialid=11 (it is not hard)
• BTW you can even easily read message in even MATLAB, if you want you can analyze the data using MATLAB. Look at this API: http://www.mathworks.com/help/matlab/matlab_external/writing-and-reading-data.html and http://www.mathworks.com/help/matlab/serial-port-devices.html
• So it looks like it is not hard to read data in Linux and Raspberry Pi. But I am new with Linux and learning how to use it now...lol

[cjackie]

Your information is very valuable. :D

Yea. I see. We can mount the raspberry pi later for doing computer vision stuff. Some intensive computing can take several seconds.

Here is some low level programming interface(for Unix like os) at operating system level regarding port series(you said it is TTY port): https://www.cmrr.umn.edu/~strupp/serial.ht Maybe I will look into it. It seems interesting.:)

For now, just focus on your final. Lol

[cjackie]

The website should be https://www.cmrr.umn.edu/~strupp/serial.html