Techniques for Power-Conscious Bus Encoding in Input/Output and Data Buses: An Examination of Embedded Systems

Abstract

In mobile computing applications, microprocessors equipped with integrated LCD controllers and Flash ROM are commonly utilized. The initial section of this research introduces a software-exclusive encoding methodology aimed at diminishing energy consumption on the processor-memory bus when displaying an image on the LCD. The core concept of this project is to employ the palette as a coding table for the picture buffer and subsequently reallocate the codes predicated on the characteristics of the image by leveraging the translation capabilities of the LCD controller. Empirical data substantiates the efficacy of this method, revealing a power reduction of 29% for text-based images and 17% for graphic-based images. The subsequent section of the paper delineates Compact, a software-exclusive encoding technique that reduces CPU transitions. Modifications are made to the device driver of the Linux operating system to implement Bus-Invert encoding whenever data is accessed from or recorded to a Compact Flash file system. The minimal software overhead facilitates a potential reduction of up to 25% in bus transition durations.