SIM802 Hardware Design
GHOST Mode
Connect charger to module’s VCHG Pin
while SIM802 is in POWER DOWN
mode.
IMPORTANT: Here GHOST mode is
OFF and Charging mode, it means that not
all software tasks are running.
z
Battery can be charged when GSM
engine is not registered to GSM
network;
z
Only a few AT commands is available
as listed below.
Note:
VBAT can not provide much more than 5mA current while SIM802 module is during the
DDLO charge state. In other words it is strongly recommended that VBAT should not be the
main power supply in the application subsystem while SIM802 module is during the DDLO
charge state.
Table 10: AT Command usually used in GHOST mode
AT command
Function
AT+CALARM
Set alarm time
AT+CCLK
Set data and time of RTC
AT+CPOWD
Power down
AT+CBC
Indicated charge state and voltage
AT+CFUN
Start or close the protocol
Set AT command
“
AT+CFUN =1
”,module
can be transferred from
GHOST
mode to
Charging in normal
mode, In
GHOST
mode , the default value is 0
3.5.5 Charger requirements
Following is the requirements of charger for SIM802.
- Simple transformer power plug
- Output voltage: 5.0V-5.25V
- Charging current limitation: 650mA
- A 10V peak voltage is allowed for maximum 1ms when charging current is switched off.
- A 1.6A peak current is allowed for maximum 1ms when charging current is switched on.
3.6 Power saving
There are two methods for the module to enter into low current consumption status.
“AT+CFUN=0” is used to set module into minimum functionality mode and DTR hardware
SIM802_HD_V2.01
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