OpenPnP is a great open source framework for building a DIY SMT Pick&Place machine. But it does not stop there: It is possible to use OpenPnP with a commercial pick & place machine, for example the Charmhigh CHM-T36VA. This Chinese machine comes with its own controller software which works but is not that great. The good news is that it is possible to hack and retrofit the machine so it can run the much more powerful OpenPnP.
Retrofitted CHM-T36VA
FreeRTOS has many cool features, and one is that it can report the CPU percentage spent in each task. The downside is that to get this kind of information some extra work is needed. In this article I show how to do this for the NXP i.MX1064.
FreeRTOS Runtime Information
Using the debugger to inspect the application data is a very convenient thing. But if the data grows and if the data set is large, it makes more sense to dump the data to the host and process it offline. GDB is the de-facto debugger engine and includes a powerful command line and scripting engine which can be used in Eclipse too.
GDB Debugger Console in Eclipse
Maker spaces and ‘FabLabs’ are popular and accessible in many areas. 3D printers are on the cheap, and powerful laser cutters are in the range of the fearless hobbyist. You can get dirty-cheap PCBs from China in less than a week (ok, probably not right now because of Corona virus) and it is easy to SMD solder parts these days with a DIY SMD PnP machine and OpenPnP. With the right equipment and skill set it is possible to build many cool projects. It is very rewarding and a great learning thing. Blog about it so other can learn too. And it even could get featured on Hackaday.
But: The risk is that someone might send you letter about a ‘Copyright Infringement’. Sadly, this is what happened to me for one of my recent projects. I don’t think that ‘take down’ letter was justified, but I learned a great deal what I should have done differently to avoid that situation. So in the end, it was a learning opportunity, which I believe is worth to share. In essence: what can a maker or educator do?
Hackaday: building a giant meta-clock made of smaller clocks (image: original image from Hackaday)
The gnuplot is a versatile and powerful tool to plot and visualize all kind of data. I wish there would be a plugin for it in Eclipse. But as this is not (yet?) the case, here is how I’m using it with gdb and Eclipse, using the MCUXpresso IDE as example.
Gnuplot with Eclipse
One great feature of Eclipse is its built-in spell checking engine. So no more excuses are possible for typos in the source code ;-). Eclipse scans the source code in the background and offers to correct it:
Eclipse Spell Checker
When using an RTOS like FreeRTOS, sooner or later you have to ask the question: how much time is spent in each task? The Eclipse based MCUXpresso IDE has a nice view showing exactly this kind of information:
FreeRTOS Runtime Information
For FreeRTOS (or that Task List view) to show that very useful information, the developer has to provide a helping hand so the RTOS can collect this information. This article shows how this can be done on an ARM Cortex-M.
In JTAG Debugging the ESP32 with FT2232 and OpenOCD I have used a FTDI FT2232 breakout board to JTAG debug with OpenOCD. With an adapter board on top of the TDI FT2232 the wiring is much easier and simpler to use:
JTAG Debugging the ESP32 with FT2232
Stack overflows are probably the number 1 enemy of embedded applications: a call to a a printf() monster likely will use too much stack space, resulting in overwritten memory and crashing applications. But stack memory is limited and expensive on these devices, so you don’t want to spend too much space for it. But for sure not to little too. Or bad things will happen.
The Eclipse based MCUXpresso IDE has a ‘Heap and Stack Usage’ view which can be used to monitor the stack usage and shows that a stack overflow happened:
Heap and Stack Usage
But this is using the help of the debugger: how to catch stack overflows at runtime without the need of a debugger? There is an option in the GNU gcc compiler to help with this kind of situation, even if it was not originally intended for something different. Continue reading
This project is about building a stepper motor clock around the NXP LPC845-BRK board. The design is using a combination of 3D printed and laser cut parts and costs below $15.
Stepper Clock Acrylic Face White Hands
MCU on Eclipse 