![SimCom SIM548C HD V1.01 Hardware Design Download Page 40](http://html1.mh-extra.com/html/simcom/sim548c-hd-v1-01/sim548c-hd-v1-01_hardware-design_1274794040.webp)
SIM548C Hardware Design
about 40ms.
z
Receiving a voice or data call from network to wake up the GSM part of the module
z
Receiveing a SMS from network to wake up the GSM part of the module
z
RTC alarm expired to wake up the GSM part of the module
Note: DTR pin should be held low level during communicating between the module and DTE.
3.7 Summary of state transitions (except SLEEP mode)
Table 12: Summary of state transitions
Further
mode
Current
mode
POWER
DOWN
Normal
mode
Ghost mode
(Charge-only
mode)
Charging in
normal
Alarm mode
POWER
DOWN
Use
PWRKEY
Connect charger
to VCHG and
connect battery to
VBAT
No direct
transition, but via
“Ghost mode” or
“Normal mode”
Switch on from
POWER DOWN
mode by RTC
Normal
mode
AT+CPOWD
or use
PWRKEY pin
Connect charger
to VCHG and
connect battery to
VBAT, then
switch off module
by AT+CPOWD
or using
PWRKEY
Connect charger
to VCHG pin of
module and
connect battery to
VBAT pin of
module
Set alarm by
“AT+CALARM
”, and then
switch off the
module. When
the timer expires,
the module turns
on and enters
Alarm mode
Ghost
mode
(Charge-
only
mode)
Disconnect
charger
No direct
transition, but
via “Charging
in normal”
mode
Turn on the
module using
PWRKEY OR
SET AT
Command
“AT+CFUN=1”
Set alarm by
“AT+CALARM
”, when the timer
expire, module
will enter Alarm
mode
SIM548C_HD_V1.01
09.05.2008
40