Chapter 8 interacted with external hardware devices connected to the GPIO pins using the Pico-series SDK. This chapter looks at interacting with the hardware directly. No new Assembly Language instructions need to be learned, because access to the hardware is accomplished with the memory load/store instructions previously studied. All hardware access is via special memory addresses connected to hardware devices, which respond based on the data written to them rather than being connected to memory. Similarly, hardware devices provide data from external sources when these addresses are read.