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Link-Time Optimization and Debugging of Object-Oriented Programs on AVR MCUs

December 15, 2021 / nebel / 0 Comments

The featured image of this post is based on a picture by TheDigitalArtist on Pixabay.

Link-time optimization (LTO) is a very powerful compiler-optimization technique. As I noticed, it does not go very well together with debugging object-oriented programs under GCC, at least for AVR MCUs. I noticed that in the context of debugging an Arduino program, and it took me quite a while to figure out that LTO is the culprit.

Lubarsky’s Law of Cybernetic Entomology: There’s always one more bug

(Who the hell is Lubarsky?)

One Line Only

October 30, 2021 / nebel / 3 Comments

The featured image of this post is by Vladimir163rus on Pixabay.

A new Arduino library has seen the light of day: SingleWireSerial. It supports single-wire, asynchronous serial, half-duplex communication. By using the input capture feature of the AVR MCUs, it is extremely accurate and supports bit rates up to 250 kbps robustly. And contrary to its title, one can even use it in a two-wire setting.

Communicating Asynchronously

October 26, 2021 / nebel / 1 Comment

The featured image of this post is by dooder – de.freepik.com

Serial asynchronous communication is one of the most common forms of communication between two electronic devices. Let us see, what Arduino libraries are there to support it, and let us check, how well they perform.

Is any Input Available?

October 21, 2021 / nebel / 3 Comments

The featured image of this post is by rawpixel.com – de.freepik.com

The SoftwareSerial class has the available() method, which returns the number of characters that have been already received but not yet read. This is very similar to what the standard Serial.available() method offers. There is an interesting difference, though. A call to SoftwareSerial.available() is significantly slower than a call to Serial.available(). We will look for the deeper reason for this strange behavior and I will show you three ways how to fix it.

EDIT: The problem will vanish with Arduino version 1.8.17

Timing the Timekeeper

October 20, 2021 / nebel / 1 Comment

The featured mage of this blog post is by Gerd Altmann from Pixabay

What is the overhead imposed by the millis() interrupt? And can we get rid of it?

Real Programmers Write Assembly Code

October 11, 2021 / nebel / 1 Comment

Although the typical Arduino programmer is probably not interested in writing assembly code, in some situations assembly programming is essential. Let’s have a look at these situations and see what one can do.

Doing it the Logical Way

October 7, 2021 / nebel / 5 Comments

When things go wrong, although your program logic appears to be correct, it is time to look at the signals going into the MCU and coming out of the MCU. The best tool for that is a logic analyzer.

Connecting the Dots

September 28, 2021 / nebel / 0 Comments

If you want to drive a 5×7 dot matrix display directly from your MCU, I have the right Arduino library for you. Flexible, easy to use, supporting low power operation, and a low memory footprint: DotMatrix5x7.

Saving Energy by Choosing the Right MCU

September 24, 2021 / nebel / 0 Comments

Featured image is by Projekt_Kaffeebart from Pixabay

In this post, I take a look at whether there are significant differences of power consumption between the different AVR MCUs. I will look at the nominal values and also measure the power consumption in reality.