GDB supports a mode which allows the GDB debug client to read memory while the target is running. This allows features like ‘live variables’: that way I can see the variables refreshed and changing over time without halting the target. Another functionality which comes with that feature is to check stopped threads or to see all threads in the system.
multiple FreeRTOS threads in debug view
Working with low power modes can be challenging. It can severely affect debugging capabilities of a microprocessor or microcontroller. I ported a FreeRTOS application using the Tickless Idle Mode to the NXP i.MX RT1064 board, and all of a sudden, the board was unresponsive to any debugger connection. Luckily the board was not really bricked, but it took me while to find a way to recover it. So for when you end up in a situation with a ‘bricked’ i.MX RT1064 board, this article might be helpful for you to recover it.
i.MX RT1064-EVK Board
As noticed in “First Steps with the NXP i.MX RT1064-EVK Board” there is a new LPC4322 based debug interface on the RT1064-EVK board.
LPC4322JET100 based Debug Interface
In “First Steps with the NXP i.MX RT1064-EVK Board” I mentioned that the board kit came with a camera module, but it was unclear to me which module was included in the kit. I know it now: it is the ON Semiconductor MT9M114 :-).
Image from the MT9M114
Dealing with variable width character encoding as with UTF-8 is pretty much a standard these days, at least in the Desktop programming world. This is not so much true when programming embedded devices and microcontroller. In any case, Eclipse has you covered. This is especially helpful dealing with non-ASCII character codes in comments:
Comment with UTF-8 in Eclipse
You might wonder what ‘Zork‘ is? Zork is one of the first and earlist fictive computer games, written around 1977 and 1979, written in MDL on a DEC PDP-10 by members of the MIT Dynamic Modelling group (see https://en.wikipedia.org/wiki/Zork). I believe the first time I have played Zork was around 1984 on a Commodore 64.
Zork
With Eclipse as IDE it is very easy to debug an application on a board. Still sometimes it is useful to get one level down and control the GDB server directly.
Monitor Flash Download
What is the life span of a cheap Chinese CO2 laser tube? I mean: how long can I use one these (aka K40) laser engraver/cutter tubes as used in that 50W machine I have? I have used my machine for over a year for now, and I don’t have hour meter, but I estimate it have used it for about 500 hours. I don’t have a data sheet of the tube used inside my machine. Discussions on the internet estimate the live span from DOA (Dead On Arrival) to ‘a few months with moderate usage’ up to 3000-5000h’. Well, whatever it would be: my laser cutter stopped working two weeks ago. Here is how I got it back operating again….
New Laser Tube on the Bench
Need a quick way how to attach a LED, a push button and two resistors to the Raspberry Pi header? One way is to use some ‘flying’ wires. Or to use three pieces of lasercut plywood for a nice looking Raspy extension board:
Wood Circuit Board on Raspberry Pi
There are things which are game changer in the world of software development: one such event was when I started using a VCS (Version Control System): it changed for me how I keep and store my projects and settings. It even changed the way how I deal with non-software related items like documents or other valuable things: I started storing them in to a VCS too.
EGit with Eclipse
Unit testing is a common practice for host development. But for embedded development this still seems mostly a ‘blank’ area. Mostly because embedded engineers are not used to unit testing, or because the usual framework for unit testing requires too many resources on an embedded target?
What I have used is the μCUnit framework which is a small and easy to use framework, targeting small microcontroller applications.
uCUnit
In my “Tutorial: Catching Rogue Memory Accesses with Eclipse and GDB Watchpoints” I have used Eclipse/CDT and GDB watchpoints. I used a conditional watchpoint, but this comes with a performance hit. In this article I show how to use the ARM Cortex trace hardware to catch specific writes to a memory location. Without severe performance degradation. But for this I need a little helper: the DEADBEEF catcher!
0xdeadbeef catcher
Eclipse is great: it gives me the tools and capabilities to solve the really hard bugs to find. An example of that ‘hard’ category are ‘rogue’ memory accesses: something in the application is accessing an unwanted memory location and corrupts the data. This might be very sporadic, or takes a long while until it happens. With normal ‘stop-mode’ debugging (setting a normal breakpoint) and stepping usually won’t let me find that bug, as it might be coming from a pointer somewhere. Maybe from an interrupt routine. Or maybe an unitialized or corrupted pointer corrupts to my memory. Usually all what I know is the memory adddress of the data, maybe what is written, but not what or who is writing to that location.
In this article I’m using one of the ‘less-known’ debugging techniques available in Eclipse and CDT and how it works: watchpoints!
Watchpoint with Condition
In this article I’m using one of the ‘less-known’ debugging techniques available in Eclipse and CDT and how it works: watchpoints!
In this short article I show you how to enable one of the hidden gems in Eclipse: how to get a description of the library function used in the code
snprintf() help text
FreeRTOS includes a nice feature to give me information about how much time every task is spending running on the system:
FreeRTOS Runtime Information
This tutorial explains that FreeRTOS Runtime Statistics feature and how it can be turned on and used.
My usual workflow is: edit – build – debug and repeat. And this for the same project again and again. So here are a few tips how to make these iterations faster with Eclipse. One thing is to use the F11 shortcut to debug the last launched/debugged application:
Debug Last Launched
The McuOnEclipse GitHub repository hosts many Processor Expert projects and is very popular (cloned more than 1000 times, thank you!). Processor Expert is a powerful framework which generates driver and configuration code, simplifying application development for a wide range of microcontroller and families. But Processor Expert won’t be developed further by NXP and is not part of MCUXpresso IDE. While it is possible to install Processor Expert into MCUXpresso IDE 10.2, how can these projects used ini an IDE *without* Processor Expert? This article describes how to port an existing Processor Expert project into the NXP MCUXpresso IDE.
Ported Project with FRDM-K64F using Adafruit SSD1351 and Processor Expert
It is never too early to start thinking about Halloween projects :-).
rendered Eyes with i.MX RT
When I ordered originally the MIMXRT1050-EVK from Mouser, it was without the LCD display (see “MCUXpresso IDE V10.1.0 with i.MX RT1052 Crossover Processor“. I ordered the LCD for the board soon after writing that article, but I was too busy with the university lectures and exams to get a hand on it. Finally I have spent a few hours at night and I proudly can say: the display is working 🙂
How can I open a project folder location in the system explorer?
Starting with Eclipse Oxygen, the project properties have a button for this in the Resource settings:
Show in System Explorer
By default, the NXP S32K144EVB and microcontroller is using a 5V supply voltage and logic levels which is great for noisy environment or any 5V devices. Many of my displays and sensors use 3.3V logic levels, so I would have to use a level shifter from 5V to 3.3V. There is another way: to change the board for 3.3V logic levels so I can use directly things like a SSD1306 display.
S32K144EVB with OLED SSD1306 using 3.3V Logic Levels
