User's Manual

GSM/GPRS Module Series
M85 Hardware Design
M85_Hardware_Design Confidential / Released 4 / 88
3.7. Serial Interfaces ..................................................................................................................... 36
3.7.1. UART Port ...................................................................................................................... 38
3.7.1.1. The Features of UART Port ............................................................................. 38
3.7.1.2. The Connection of UART Port ......................................................................... 39
3.7.1.3. Firmware Upgrade ........................................................................................... 40
3.7.2. Debug Port ..................................................................................................................... 41
3.7.3. Auxiliary UART Port ....................................................................................................... 42
3.7.4. UART Application ........................................................................................................... 42
3.8. Audio Interfaces ..................................................................................................................... 44
3.8.1. Decrease TDD Noise and Other Noise .......................................................................... 45
3.8.2. Microphone Interfaces Design ....................................................................................... 46
3.8.3. Receiver and Speaker Interface Design ........................................................................ 46
3.8.4. Earphone Interface Design ............................................................................................ 48
3.8.5. Loud Speaker Interface Design...................................................................................... 49
3.8.6. Audio Characteristics ..................................................................................................... 49
3.9. SIM Card Interfaces .............................................................................................................. 50
3.10. SD Card Interface .................................................................................................................. 53
3.11. PCM Interface ........................................................................................................................ 55
3.11.1. Configuration .................................................................................................................. 56
3.11.2. Timing ............................................................................................................................. 56
3.11.3. Reference Design .......................................................................................................... 58
3.11.4. AT Command ................................................................................................................. 58
3.12. ADC ....................................................................................................................................... 59
3.13. Behaviors Of The RI .............................................................................................................. 60
3.14. Network Status Indication ...................................................................................................... 62
3.15. Operating Status Indication ................................................................................................... 62
4 Antenna Interface ............................................................................................................................... 64
4.1. Reference Design .................................................................................................................. 64
4.2. RF Output Power ................................................................................................................... 65
4.3. RF Receiving Sensitivity ........................................................................................................ 65
4.4. Operating Frequencies .......................................................................................................... 66
4.5. Antenna Requirement ........................................................................................................... 66
4.6. RF Cable Soldering ............................................................................................................... 67
5 Electrical, Reliability and Radio Characteristics ............................................................................ 68
5.1. Absolute Maximum Ratings................................................................................................... 68
5.2. Operating Temperature ......................................................................................................... 69
5.3. Power Supply Ratings ........................................................................................................... 69
5.4. Current Consumption ............................................................................................................ 70
5.5. Electro-static Discharge ........................................................................................................ 72
6 Mechanical Dimensions .................................................................................................................... 74
6.1. Mechanical Dimensions of Module ....................................................................................... 74
6.2. Recommended Footprint ....................................................................................................... 76
6.3. Top View of the Module ......................................................................................................... 77