There are two major additions to this fourth edition. First, this version supports both the TM4C and the MSP432 architectures. The material for the LM3S series has been removed. Volumes 1 and 2 focused on the hardware and software aspects I/O interfacing. In this volume we provide a set of low level device drivers allowing this volu me to focus on real-time operating systems, digital signal processing, control systems, and the internet of things. The second addition is Bluetooth Low Energy (BLE), which will be implemented by interfacing a CC2650, in a similar manner with which IEEE802.11b wifi is implemented in this book using the CC3100. Running on the CC2650 will be an application programmer interface called Simple Network Processor (SNP). SNP allows the TM4C123/MSP432 microcontroller to implement BLE using a simple set of UART messaging. Off-loading the BLE functions to the CC2650 allows the target microcontroller to implement system level functions without the burden of satisfying the real-time communication required by Bluetooth. me to focus on real-time operating systems, digital signal processing, control systems, and the internet of things. The second addition is Bluetooth Low Energy (BLE), which will be implemented by interfacing a CC2650, in a similar manner with which IEEE802.11b wifi is implemented in this book using the CC3100. Running on the CC2650 will be an application programmer interface called Simple Network Processor (SNP). SNP allows the TM4C123/MSP432 microcontroller to implement BLE using a simple set of UART messaging. Off-loading the BLE functions to the CC2650 allows the target microcontroller to implement system level functions without the burden of satisfying the real-time communication required by Bluetooth.