User's Manual

HE910 Hardware User Guide
1vv0300925 Rev.28 – 2015-06-24
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 6 of 6
7.3.1 RF Signal Requirements .......................................................................................................................................... 52
7.3.2 GPS Antenna Polarization ...................................................................................................................................... 53
7.3.3 GPS Antenna Gain .................................................................................................................................................. 54
7.3.4 Active versus Passive Antenna ............................................................................................................................... 54
7.3.5 GPS Antenna - PCB Line Guidelines ........................................................................................................................ 55
7.3.6 RF Trace Losses....................................................................................................................................................... 55
7.3.7 Implications of the Pre-select SAW Filter ............................................................................................................... 56
7.3.8 External LNA Gain and Noise Figure....................................................................................................................... 56
7.3.9 Powering the External LNA (active antenna) ......................................................................................................... 56
7.3.10 External LNA Enable ............................................................................................................................................. 57
7.3.11 Shielding ............................................................................................................................................................... 58
7.3.12 GPS Antenna - Installation ................................................................................................................................... 58
8 LOGIC LEVEL SPECIFICATIONS .................................................................................................................................. 59
8.1 U NCONDITIONAL S HUTDOWN ............................................................................................................................................... 60
9 USB PORT ................................................................................................................................................................ 61
9.1 USB 2.0 HS D ESCRIPTION ................................................................................................................................................... 61
10 SPI PORT ................................................................................................................................................................. 62
10.1 SPI C ONNECTIONS ............................................................................................................................................................ 63
11 USB HSIC ................................................................................................................................................................. 64
12 SERIAL PORTS .......................................................................................................................................................... 65
12.1 MODEM SERIAL PORT 1 (USIF0) ................................................................................................................................... 66
12.2 MODEM SERIAL PORT 2 (USIF1) ................................................................................................................................... 68
12.3 RS232 LEVEL TRANSLATION ................................................................................................................................................ 69
13 AUDIO SECTION OVERVIEW .................................................................................................................................... 71
13.1 E LECTRICAL C HARACTERISTICS ............................................................................................................................................. 71
13.1.1 CODEC Examples .................................................................................................................................................. 71
14 GENERAL PURPOSE I/O ........................................................................................................................................... 72
14.1 GPIO L OGIC LEVELS .......................................................................................................................................................... 73
14.2 U SING A GPIO P AD AS INPUT ........................................................................................................................................... 74
14.3 U SING A GPIO P AD AS OUTPUT ........................................................................................................................................ 74
14.4 I NDICATION OF NETWORK SERVICE AVAILABILITY ..................................................................................................................... 75
14.5 RTC B YPASS OUT ............................................................................................................................................................. 76
14.6 E XTERNAL SIM H OLDER I MPLEMENTATION ........................................................................................................................... 76
14.7 VAUX P OWER O UTPUT ..................................................................................................................................................... 76
14.8 ADC C ONVERTER ............................................................................................................................................................. 77
14.8.1 Description ........................................................................................................................................................... 77
14.8.2 Using ADC Converter ............................................................................................................................................ 77
15 MOUNTING THE HE910 ON THE APPLICATION ........................................................................................................ 78
15.1 G ENERAL ........................................................................................................................................................................ 78
15.2 M ODULE FINISHING & DIMENSIONS ..................................................................................................................................... 78
15.3 R ECOMMENDED FOOT PRINT FOR THE APPLICATION ................................................................................................................. 80
15.4 S TENCIL .......................................................................................................................................................................... 81