User Manual

XT55/56 Hardware Interface Description
Confidential / Preliminary
s
XT55/56_hd_v02.96 Page 53 of 125 18.08.2005
Wake up XT55/56 from SLEEP Mode
A wake-up event is any event that causes the module to draw current. Depending on the
selected mode the wake-up event either switches SLEEP mode off and takes XT55/56 back
to AT+CFUN=1, or activates XT55/56 temporarily without leaving the current SLEEP mode.
Definitions of the state transitions described in Table 11:
Quit = XT55/56 exits SLEEP mode and returns to AT+CFUN=1.
Temporary = XT55/56 becomes active temporarily for the duration of the event and the
mode-specific follow-up time after the last character was sent or received
on the serial interface.
No effect: = Event is not relevant in the selected SLEEP mode. XT55/56 does not
wake up.
Table 11: Wake-up events in NON-CYCLIC and CYCLIC SLEEP modes
Event Selected mode
AT+CFUN=0
Selected mode
AT+CFUN=5 or 6
Selected mode
AT+CFUN=7, 8, 9
Ignition line No effect No effect No effect
GSM_RTS0 or GSM_RTS1
1)
(falling edge)
Quit + flow control No effect, GSM_RTS
is only used for flow
control
Mode 7 and 8: No
effect, GSM_RTS is
only used for flow
control
Mode 9: Temporary +
flow control
Unsolicited Result Code
(URC)
Quit Quit Temporary
Incoming voice or data call Quit Quit Temporary
Any AT command
(incl. outgoing voice or data
call, outgoing SMS)
Not possible
(UART disabled)
Temporary Temporary
Incoming SMS depending on
mode selected by AT+CNMI:
AT+CNMI=0,0 (= default, no
indication of received SMS)
AT+CNMI=1,1 (= displays
URC upon receipt of SMS)
No effect
Quit
No effect
Quit
No effect
Temporary
GPRS data transfer Not possible
(UART disabled)
Temporary Temporary
RTC alarm Quit
2)
Quit Temporary
AT+CFUN=1 Not possible
(UART disabled)
Quit Quit
1)
See section 3.6.5.1 on wake-up via GSM_RTS.
2)
Recommendation: In NON-CYCLIC SLEEP mode, you can set an RTC alarm to wake
up XT55/56 and return to full functionality. This is a useful approach because, in this
mode, the AT interface is not accessible.