Interrupt driven expanded option select interface for portable device

摘要

A peripheral component ( 104 ) is attached to a portable electronic device ( 102 ), and indicates an option class of the peripheral component by use of an option select circuit. The option select circuit causes an interrupt to be generated in the portable electronic device, which then determines the option class by changing the logic levels of various option select lines. If an inversion of the logic state of one of the option select lines is detected, then the portable electronic device knows an option select circuit is present, and determines the option class of the peripheral component accordingly.