Concepts
The shared concepts every tutorial assumes: board layers, pin numbering, logic levels and the three buses — explained once, with real boards.
Cross-board concept guides. Each one answers a single question and grounds every claim in the fixed sources on the board pages — no unsourced generalities.
Sections
- Concepts
The shared concepts every tutorial assumes: board layers, pin numbering, logic levels and the three buses — explained once, with real boards.
Guides
- Chip, module, board — the three layers of every dev board
Why the same name appears on a chip, a metal can, and a circuit board. How to tell which layer a claim belongs to, with all four MCUID boards as examples.
- Pin numbers, GPIO numbers and pin functions — three different things
Physical pin position, GPIO number and silk-screen function name answer different questions. Why the same on-board device can move to a different GPIO and header position across revisions, with examples from all four boards.
- 3.3 V and 5 V — power rails, logic levels and the one diode rule
Where 5 V appears on a dev board, why the GPIOs are 3.3 V logic, and the Pico ADC reverse-diode limit stated in its datasheet. What we can and cannot claim without a per-chip abs-max field.
- UART, I2C and SPI — what the three buses are, and how to check a pin before you wire it
The three wired protocols every tutorial assumes, seen through real pins on real boards — then the three-layer check that tells you whether the pin you picked actually works: SDK default, chip mux, board wiring.