This text explores the value of understanding hardware fundamentals in embedded systems development. It contrasts the modern approach, relying on frameworks and libraries, with the traditional approach, based on datasheets. The author highlights how Wozniak built systems by understanding the hardware fully. Modern tools lower the barrier to entry but can lead to a lack of understanding of underlying principles. The author emphasizes the importance of reading datasheets to grasp how hardware components function. A personal anecdote about building a counter illustrates the value of understanding the hardware's principles. The QUAD7SHIFT library is presented as an example of effectively applying datasheet knowledge, resulting in a robust, flicker-free display driver. The author stresses that understanding device behavior, like the 74HC595 shift register, leads to better code. The core logic of hardware, like the 74HC595, remains consistent despite technological advancements. He suggests using modern tools but supplementing them with a deep understanding of the hardware, by reading the datasheets. The author concludes that the old approach, based on a solid understanding of datasheets, is the foundation for reliable embedded systems. This foundation is essential to build systems that work correctly and that can be easily debugged. The key takeaway is to embrace modern tools while simultaneously cultivating a deep understanding of the underlying hardware by reading and understanding the datasheets.