4.3 Interfaces

I declare: solidlikelyshaky

1. Explain 3.3 V and 5 V logic levels, what is compatible, and build a level shifter when needed.
2. Explain why I²C wants pull-up resistors, size them, and observe the bus on the oscilloscope or logic analyzer.
3. Connect one sensor over I²C and another over SPI, and say when you choose one or the other.
4. Read a UART frame on the logic analyzer and recover the baud rate and the bytes.
5. Explain what CAN brings to a bike or a tool pack (two wires, robust, several nodes) and read a frame with an adapter.
6. Explain RS-485 and 1-Wire, where they’re found (long distances, temperature sensors), and the notion of what USB does beyond UART.
7. Diagnosis: an I²C bus that freezes, spot the slave holding SDA low and the clocking manoeuvre that frees it.