Fast and Effective Embedded Systems Design, 2nd Edition

Chapter 15

Hardware Insights

Clocks, Resets, and Power Supply

Abstract

Two of the most fundamental hardware things to manage when applying microcontrollers are power supply and clock source. This chapter investigates in some detail the way that power is supplied to the mbed and LPC1768, and how the clock source can be selected and manipulated. This clock source setting then has a major impact on power supply. Developing from this, there is a major section on low-power operation, and the use of batteries. Linked to these is how program execution is launched, either after power-up or major discontinuity; this leads to concepts of reset, watchdog timer and brownout. As the mbed itself is not designed for power-conscious applications, the chapter ends ...