Quectel M20

M20 Hardware Design
Contents
0 Revision history .............................................................................................................................8
1 Introduction....................................................................................................................................9
1.1 Related documents ...............................................................................................................9
1.2 Terms and abbreviations.....................................................................................................10
1.3 Safety caution.....................................................................................................................12
2 Product concept............................................................................................................................14
2.1 Key features .......................................................................................................................14
2.2 Functional diagram.............................................................................................................16
2.3 Evaluation board ................................................................................................................17
3 Application interface....................................................................................................................18
3.1 Pin description....................................................................................................................18
3.2 Operating modes ................................................................................................................22
3.3 Power supply ......................................................................................................................23
3.3.1 Power supply pins ....................................................................................................25
3.3.2 Minimizing power losses..........................................................................................25
3.3.3 Monitoring power supply .........................................................................................26
3.4 Power up and power down scenarios .................................................................................26
3.4.1 Turn on .....................................................................................................................26
3.4.2 Turn off.....................................................................................................................29
3.4.3 Restart module using the PWRKEY pin...................................................................32
3.5 Charging interface..............................................................................................................33
3.5.1 Battery pack characteristics......................................................................................34
3.5.2 Recommended battery pack .....................................................................................35
3.5.3 Implemented charging technique..............................................................................36
3.5.4 Operating modes during charging ............................................................................38
3.5.5 Charger requirements ...............................................................................................39
3.6 Power saving ......................................................................................................................40
3.6.1 Minimum functionality mode...................................................................................40
3.6.2 SLEEP mode ............................................................................................................40
3.6.3 Wake up module from the SLEEP mode..................................................................41
3.7 Summary of state transition (except SLEEP mode) ...........................................................41
3.8 RTC backup .......................................................................................................................41
3.9 Serial interface ...................................................................................................................43
3.9.1 Function of serial port 0 & serial port 1 ...................................................................45
3.9.2 Software upgrade and software debug......................................................................46
3.10 Audio interfaces................................................................................................................48
3.10.1 Microphone interface configuration .......................................................................49
3.10.2 Speaker interface configuration..............................................................................51
3.10.3 Earphone interface configuration ...........................................................................53
3.10.4 DAI interface（optional）.....................................................................................54
3.11 SIM card interface ............................................................................................................55
M20_HD_V1.01 - 2 -
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