SIM802 Hardware Design
SIM802_HD_V2.01
12.01.2010
28
STATUS
（
OUTPUT
）
V
IL
<0.2*VBAT
V
IH
> 0.6*VBAT
Pulldown > 2s
Hiz
VBAT
PWRKEY
(INPUT)
Figure 8 Timing of turn on system
When power on procedure completed, SIM802 will send out following result code to indicate the
module is ready to operate, when set as fixed baud rate. STATUS Pin will drive to 2.8V and keep
this level when in work mode. If configured to a fixed baud rate, SIM802 will send the result code
“RDY” to indicate that it is ready to operate. This result code does not appear when autobauding
is active.
3.4.1.2 Turn on the SIM802 using the VCHG signal
As described in chapter 3.4, charger can be connected to SIM802’s VCHG Pin regardless of the
module’s operating mode.
If the charger is connected to the module’s VCHG Pin while SIM802 is in POWER DOWN mode,
SIM802 will go into the GHOST mode (Off and charging). In this mode, the module will not
register to network, and only a few AT commands can work in this mode. For detailed
information please refers to chapter 3.5.
When module is powered on using the VCHG signal, SIM802 sends out result code as following
when fixed baud rate:
RDY
GHOST MODE
In GHOST mode, by driving the PWRKEY to a low level voltage for period time (Please refer to
the power on scenarios in 3.4), SIM802 will power up and go into charge mode (charging in
normal mode), all operation and AT commands can be available. In this case, SIM802 will send
out result code as following:
