
WA_DEV_W218_PTS_002 Rev 006 April 29, 2010 8
Product Technical Specification &
Customer Design Guidelines
3.6. Main Serial Link (UART) ............................................................................................. 37
3.6.1. Features .............................................................................................................. 37
3.6.2. Pin Description .................................................................................................... 37
3.6.2.1. 5-wire Serial Interface Hardware Design................................................................... 38
3.6.2.2. 4-wire Serial Interface Hardware Design................................................................... 38
3.6.2.3. 2-wire Serial Interface Hardware Design................................................................... 38
3.6.3. Application........................................................................................................... 38
3.6.3.1. V24/CMOS Possible Design .................................................................................... 40
3.7. SIM Interface.............................................................................................................. 42
3.7.1. Features .............................................................................................................. 42
3.7.2. Pin Description .................................................................................................... 43
3.7.3. Application........................................................................................................... 44
3.7.3.1. SIM Socket Connection ........................................................................................... 44
3.8. General Purpose Input/Output .................................................................................... 45
3.8.1. Pin Description .................................................................................................... 45
3.9. Analog to Digital Converter ......................................................................................... 46
3.9.1. Features .............................................................................................................. 46
3.9.2. Pin Description .................................................................................................... 46
3.10. Analog Audio Interface................................................................................................ 47
3.10.1. Microphone Features........................................................................................... 47
3.10.1.1. Electrical Characteristics........................................................................................ 47
3.10.2. Speaker Features ................................................................................................ 48
3.10.2.1. Speakers Outputs Power ....................................................................................... 48
3.10.3. Pin Description .................................................................................................... 49
3.10.4. Application........................................................................................................... 49
3.10.4.1. Microphone ........................................................................................................... 49
3.10.4.2. Speaker SPKP and SPKN ..................................................................................... 52
3.10.5. Design Recommendation..................................................................................... 53
3.10.5.1. General ................................................................................................................. 53
3.10.5.2. Recommended Microphone Characteristics............................................................ 53
3.10.5.3. Recommended Speaker Characteristics................................................................. 54
3.10.5.4. Recommended Filtering Components..................................................................... 54
3.10.5.5. Audio Track and PCB Layout Recommendation ..................................................... 56
3.11. Pulse-Width Modulators (PWMs) ................................................................................ 58
3.11.1. Features .............................................................................................................. 58
3.11.2. Pin Description .................................................................................................... 58
3.11.3. Application........................................................................................................... 58
3.12. BUZZER Output ......................................................................................................... 60
3.12.1. Features .............................................................................................................. 60
3.12.2. Pin Description .................................................................................................... 60
3.12.3. Application........................................................................................................... 60
3.12.3.1. Calculations of the Low Filter ................................................................................. 62
3.12.3.2. Recommended Characteristics for the Buzzer ........................................................ 62
3.13. ON/~OFF Signal ......................................................................................................... 63
3.13.1. Features .............................................................................................................. 63
3.13.2. Pin Description .................................................................................................... 63
3.13.3. Application........................................................................................................... 64
3.13.3.1. Power ON ............................................................................................................. 64
3.13.3.2. Power OFF............................................................................................................ 66
3.14. WISMO_READY Indication......................................................................................... 67