Browse Prior Art Database

KEYPAD SCROLLING

IP.com Disclosure Number: IPCOM000007705D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-16
Document File: 3 page(s) / 110K

Publishing Venue

Motorola

Related People

Abdul Mujid bin Kassim: AUTHOR

Abstract

A 'Wrong Number' call, especially when it is a long distant call can be costly. Presently no way to verify the number for the radio telephone without a front panel display Installing the display is not always the answer to the problem, especially for space sen- sitive applications and because the installation may require major casing redesign.

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Page 1 of 3

Technical Developments

KEYPAD SCROLLING

by Abdul Mujid bin Kassim

  A 'Wrong Number' call, especially when it is a long distant call can be costly. Presently no way to verify the number for the radio telephone without a front panel display Installing the display is not always the answer to the problem, especially for space sen- sitive applications and because the installation may require major casing redesign.

Thus, keypad scrolling method can overcome this problem. The keypad is made ofclear silicon rubber

with LEDs embedded underneath every key that can be driven individually. To minimize the effect ofthe adjacent LEDs the:,SMT-TOPLED" or equiv- alent SMT led can be used. The silicon rubber itself can be designed as a light-pipe.

  SPI compatible SIP6 driver can be used to drive LEDs with minimum chip count. Row or column scanning method can further reduce chip count as shown in Figure 1.

Fig. 1 Keypad Scrolling Assembly

0 Momrol.3. I"C. 1996 156 May I996

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M-LA Technical Developments

Below is the example to drive LED 'l', '*' and '#' :_

  Step 1. Force the row ofthe desired digit, in this case Row 1, to output low and other rows to output high. Set column of the desired digit, in this case, Co1 1 to output high and other column to low. Thus, LED '1' will light up.

  Step 2. Force Row 4 to output low and Row 1,2 and 3 to output high. Set Co1 1 and Co1 3 to output high and Co1 2 to output low. LED '*' and '#' will light up.

  When step 1 and step 2 repeated at 5 ms inter- val the LED 'l', '*' and '#' will appear to be lighted up simultaneously.

  The operation mode of the keypad scrolling is controlled by the software and should be program- mable. After a specified period after the last key was pressed, the keypad scrolling mode will be activated. This idle time is to eliminate the user entry inter- ruption and only activate t...