UC864-G Hardware User Guide
DRAFT
- 29/10/07
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 4 of 66
10.2
General Design Rules ..........................................................................................................40
10.3
Other considerations ...........................................................................................................40
10.4
Microphone Biasing .............................................................................................................41
10.4.1
Balanced Microphone Biasing ....................................................................................................... 41
10.4.2
Unbalanced Microphone Biasing................................................................................................... 42
10.5
Microphone Buffering ..........................................................................................................44
10.5.1
Buffered Balanced Mic................................................................................................................... 44
10.5.2
Buffered Unbalanced (Single Ended) Microphone ........................................................................ 46
11
OUTPUT LINES (Speaker)..............................................................................................49
11.1
Short description..................................................................................................................49
11.2
Output Lines Characteristics ..............................................................................................50
11.3
General Design Rules ..........................................................................................................51
11.3.1
Noise Filtering................................................................................................................................ 51
11.4
Handset Earphone Design...................................................................................................52
11.5
Hands-Free Earphone (Low Power) Design.......................................................................53
11.6
Car Kit Speakerphone Design .............................................................................................54
12
General Purpose I/O.......................................................................................................55
12.1
Logic level specifications ....................................................................................................56
12.2
Using a GPIO Pad as INPUT ................................................................................................57
12.3
Using a GPIO Pad as OUTPUT ............................................................................................57
12.4
Using the RFTXMON Output GPIO5....................................................................................57
12.5
Using the Alarm Output GPIO6 ...........................................................................................57
12.6
Using the Buzzer Output GPIO7..........................................................................................58
12.7
Indication of network service availability...........................................................................59
12.8
RTC Bypass out....................................................................................................................60
12.9
VAUX1 power output............................................................................................................60
13
DAC and ADC section....................................................................................................61
13.1
DAC Converter(TBD) ............................................................................................................61
13.1.1
Description..................................................................................................................................... 61
13.1.2
Enabling DAC ................................................................................................................................ 61
13.1.1
Low Pass Filter Example ............................................................................................................... 62
13.2
ADC Converter......................................................................................................................63
13.2.1
Description..................................................................................................................................... 63
13.2.2
Using ADC Converter .................................................................................................................... 63
13.3
Mounting UC864-G on your board ......................................................................................64
13.3.1
Debug of the UC864-G in production ............................................................................................ 65