Specifications

XT55 Hardware Interface Description
Confidential / Preliminary
s
mo b i l e
XT55_hd_v00.02 Page 3 of 116 17.03.2004
Contents
0 Document history....................................................................................................... 8
1 Introduction ................................................................................................................ 9
1.1 Related documents ............................................................................................. 9
1.2 Terms and abbreviations....................................................................................10
1.3 Type approval ....................................................................................................14
1.4 Safety precautions .............................................................................................16
2 Product concept........................................................................................................18
2.1 XT55 key features at a glance ...........................................................................19
2.2 Circuit concept ...................................................................................................22
3 GSM/GPRS application interface .............................................................................25
3.1 GSM/GPRS operating modes ............................................................................25
3.2 Power supply .....................................................................................................27
3.2.1 Power supply pins on the board-to-board connector.............................27
3.2.2 Minimizing power losses.......................................................................28
3.2.3 Monitoring power supply.......................................................................28
3.3 Power up / down scenarios ................................................................................29
3.3.1 Turn on the GSM/GPRS part of XT55 ..................................................29
3.3.1.1 Turn on the GSM/GPRS part of XT55 using the ignition line
GSM_IGT (Power on)...........................................................30
3.3.1.2 Timing of the ignition process...............................................31
3.3.1.3 Turn on the GSM/GPRS part of XT55 using the
GSM_POWER signal ...........................................................32
3.3.1.4 Turn on the GSM/GPRS part of XT55 using the RTC (Alarm
mode) ...................................................................................32
3.3.2 Turn off the GSM/GPRS part of XT55 ..................................................34
3.3.2.1 Turn off GSM/GPRS part of the XT55 module using AT
command..............................................................................34
3.3.2.2 Maximum number of turn-on / turn-off cycles........................35
3.3.2.3 Emergency shutdown using GSM_EMERGOFF pin .............35
3.3.3 Automatic shutdown .............................................................................36
3.3.3.1 Temperature dependent shutdown .......................................36
3.3.3.2 Temperature control during emergency call..........................37
3.3.3.3 Undervoltage shutdown if battery NTC is present.................37
3.3.3.4 Undervoltage shutdown if no battery NTC is present............38
3.3.3.5 Overvoltage shutdown..........................................................38
3.4 Automatic GPRS Multislot Class change............................................................39
3.5 GSM charging control ........................................................................................40
3.5.1 Battery pack characteristics..................................................................42
3.5.2 Recommended battery pack specification ............................................43
3.5.3 Implemented charging technique..........................................................44
3.5.4 Operating modes during charging ........................................................45
3.5.5 Charger requirements ..........................................................................46
3.6 Power saving .....................................................................................................47
3.6.1 No power saving (AT+CFUN=1)...........................................................47
3.6.2 NON-CYCLIC SLEEP mode (AT+CFUN=0) .........................................47
3.6.3 CYCLIC SLEEP mode (AT+CFUN=5, 6, 7, 8) ......................................47
3.6.4 CYCLIC SLEEP mode AT+CFUN=9 ....................................................48