Physics of the GPIO Interface
With the popularity of the Raspberry Pi, many students without an electronics foundation are exploring the GPIO interface for the first time. This sometimes leads to problems and limitations because of missing vital concepts and understanding.
I believe this can be largely avoided with a little bit of introduction. This chapter examines the electronic characteristics of the GPIO pins as inputs and outputs (and interfacing CMOS devices generally). I have used LTspice to model an equivalent circuit so that the currents and voltages can be visually plotted for ease of understanding. This chapter will equip ...