Interface between a base module and a detachable faceplate in an in-dash automotive accessory

摘要

Described herein is an in-dash automotive accessory having a detachable faceplate with a keypad and a medium resolution color graphics display. The graphic display has a rectangular array of addressable pixels. A serial interface is used to transfer data to and from the faceplate. Although the serial interface has a clock rate of only 7.5 MHz, it allows refreshing of a 64x256 pixel display panel at a 70 Hz pixel refresh rate. This is accomplished through a variety of techniques, including the use of efficient command code protocol, by packing or compressing pixel intensity data, and by double buffering incoming control messages.