IN THIS CHAPTER
Months have passed since the inception of Project Trailblazer, and the engineers have experienced success after success while developing with embedded Linux. As fall approaches, the engineers forge ahead with two temperature-related interfacing tasks: temperature sensing and temperature display. Silverjack management wants to provide accurate temperature readings from all key mountain locations and facilities to guests, visitors, employees, and the Operations Department. More than just a convenience, accurate temperature readings serve a safety role, permitting guests and employees to make informed decisions that could affect their well-being. The Project Trailblazer engineers want to acquire temperature readings at all locations and facilities, both outside and in equipment rooms. Management wants a large temperature display at each lift access point. The display should show the temperature in Fahrenheit and Celsius, at both the bottom and top of each lift.
The engineers need to develop cost-effective solutions that connect temperature sensors and large light-emitting diode (LED) displays to their target platforms. They have found inexpensive temperature sensors and LED display drivers that communicate by using synchronous serial communication. More specifically, they have found serial peripheral interface (SPI) and inter-integrated circuit (I2C) devices that connect to microprocessors using clocked serial data communication. In this chapter, we'll follow the engineers as they connect an SPI temperature sensor and I2C LED display drivers to their embedded Linux target boards.