SAN3010

PDS038-SA2531/2-003

Rev. B

21-03-00

This application note describes a simple interface for keyboard entry to the SA253x family via a Microcontroller. It

also includes hardware description , flowchart and a software example based on the 80Cxx - family of

Microcontrollers.

•

only 5 outputs and 1 input required from µC for handshake to access all keys in the SA253x keyboard matrix

•

universal interface, not restricted to specific Microcontrollers

•

supports both 3V- and 5V- µCs

•

same hardware for all single chip telephones : SA2531/2

•

same software for all single chip telephones, only key labels must be replaced

Table of Contents

1 SCOPE .............................................................................................................................................................................................................1

2 KEY FEATURES ..............................................................................................................................................................................................1

3 OTHER APPLICABLE DOCUMENTS AND PAPERS ......................................................................................................................................1

4 REVISION STATUS .........................................................................................................................................................................................2

5 GENERAL DESCRIPTION ...............................................................................................................................................................................2

6 HARDWARE CONFIGURATION ......................................................................................................................................................................2

7 APPLICATION SCHEMATIC:...........................................................................................................................................................................2

8 SCANNING TABLE/FLOWCHART...................................................................................................................................................................3

9 SAMPLE SOFTWARE......................................................................................................................................................................................3

10 KEY ENTRY SIGNAL TABLE: .......................................................................................................................................................................4

11 APPENDIX A: APPLICATION SCHEMATIC ..................................................................................................................................................5

12 APPENDIX B: FLOWCHART: ........................................................................................................................................................................6

13 APPENDIX C: SAMPLE SOFTWARE LISTING .............................................................................................................................................7

14 LIABILITY AND COPYRIGHT STATEMENT ................................................................................................................................................13

1. Data Sheet SA2531, SA2532

2. Pin-out Comparison SA2531/2

3. Product Presentation

4. Single Chip Telephone Evolution (Apr. 16, 1996)

sames

sames

sames

sames

SAN3010

APPLICATION NOTE

SINGLE CHIP TELEPHONE INTERFACE FOR

KEYBOARD ENTRY VIA uC

1 Scope

2 Key Features

3 Other applicable documents and papers