Handheld electronic device, cursor positioning sub-system and method employing cursor scaling control

A handheld electronic device comprising:

• an input sub-system comprising a cursor positioning device adapted to output a plurality of device pulses;
• an output sub-system comprising a display including a cursor;
• an operating system adapted to receive cursor movement events;
• a plurality of applications including a plurality of predetermined scaling values;
• a processor cooperating with said input sub-system, said output sub-system and said operating system to move said cursor;
• and
• a cursor controller routine adapted be controlled by said operating system or by said applications to learn which one of said applications is active and to automatically scale a number of said cursor movement events for a corresponding number of said device pulses based upon a corresponding one of said predetermined scaling values of the active one of said applications, said cursor controller routine comprising:
• a movement detection routine adapted to repetitively input said device pulses of said cursor positioning device, count said device pulses for each of four different directions, and determine whether a count for any of said different directions is equal to a predetermined count and, if so, responsively output a direction pulse, and
• a velocity detection routine adapted to input said direction pulse for each of said different directions, determine a time between successive ones of said direction pulses for each of said different directions, determine one of a plurality of modes based upon said time, and responsively adjust and output said number of said cursor movement events to said operating system.

A method of positioning a cursor for a handheld electronic device including an operating system and a plurality of applications having a plurality of predetermined scaling values, said method comprising:

• employing a cursor positioning device to output a plurality of device pulses;
• repetitively inputting said device pulses and responsively outputting to said operating system a plurality of cursor movement events;
• and
• learning which one of said applications is active and automatically scaling a number of said cursor movement events for a corresponding number of said device pulses based upon a corresponding one of said predetermined scaling values of the active one of said applications.