Interrupt driven expanded option select interface for portable device
AssigneeMotorola, Inc.
InventorsSybren D. Smith, Joseph Patino
Life of this patent
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Abstract
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.
Claims14
An option select circuit for use in a peripheral component to be connected to a portable electronic device at a connector, the connector providing a supply and a ground to the peripheral component, the option select circuit comprising:
- first and second option select lines;
- an active inverter element disposed between the first and second option select lines, the active inverter element causing at least one of the first and second option select lines to be at a logic level zero when the peripheral component is connected to the portable electronic device, wherein the first option select line and the second option select line are included in an electrical interface between the peripheral component and the portable electronic device.
A method of detecting the presence and type of a peripheral component attached to a portable electronic device, comprising:
- connecting the peripheral component to the portable electronic device;
- providing a supply voltage and a ground to the peripheral component in response to connecting the peripheral component to the portable electronic device;
- detecting a transition from a logic level one to a logic level zero on at least one of a first option select line and a second option select line, wherein the transition from a logic level one to a logic level zero on at least one of the first option select line and the second option select line is due to an active inverter element coupled between the first option select line and the second option select line in the peripheral component, and wherein the first option select line and the second option select line are included in an electrical interface between the peripheral component and the portable electronic device;
- determining an option class of the peripheral component by applying a logic level zero to at least one of the first option select line and the second option select line.
A method of indicating the presence and type of a peripheral component attached to a portable electronic device, comprising:
- connecting the peripheral component to the portable electronic device;
- receiving a supply voltage and a ground from the portable electronic device;
- causing a transition from a logic level one to a logic level zero on at least one of a first option select line and a second option select line, performed by an active inverter element coupled between the first option select line and the second option select line, wherein the first option select line and the second option select line are included in an electrical interface between the peripheral component and the portable electronic device;
- in response to one of the first option select line and second option select line having a logic level zero applied to it by the portable electronic device, inverting a logic level of the other of the first option select line and second option select line, performed by the active inverter element coupled between the first option select line and the second option select line.
Dependencies are inferred from the claim text.