Keypad scanner process and device and cordless telephone employing the mechanism

A method for scanning a keypad comprised of more than one key, said keypad being incorporated with an integrated circuit including a microcontroller, comprising the steps of:

• detecting depression of at least one of said keys on said keypad;
• triggering a wake up of said integrated circuit in response to said detecting;
• and
• debouncing said keys using software, wherein said software comprises the steps of;
• receiving an interrupt signal at an interrupt port when one of said keys is depressed;
• masking said interrupt port for a predetermined amount of time;
• and
• reading a keypad status register to obtain a stable identity of said depressed key after said predetermined amount of time.

A keypad scanner mechanism including a keypad having more than one key, incorporated with an integrated circuit including a microcontroller, comprising:

• an activity detect mode for determining when at least one of said keys has been depressed;
• a normal mode, triggered when at least one of said keys has been depressed during activity detect mode, for identifying and reporting to said microcontroller depression of said keys;
• a multiple keys down code reported whenever two or more keys are simultaneously depressed;
• a status register for disclosing a stable identity of a debounced key;
• and
• an interrupt signal, generated if at least one of said keys is depressed since said status register was last read, said interrupt signal interrupts said microprocessor so that an interrupt port can be masked for a predetermined amount of time, said status register being read to obtain a stable identity of said key depression after said predetermined time has expired.