SimCom SIM7020E - Power off

Smart Machine Smart Decision
SIM7020_Hardware_Design_V1.02 19 2018-07-25
port ready
V
IH
Input high level voltage on PWRKEY pin
0.7*VBAT
V
V
IL
Input low level voltage on PWRKEY pin 0.3*VBAT V
3.4.2 Power off
The following methods can be used to power off SIM7020.
 Method 1: Power off SIM7020 by pulling the PWRKEY pin to ground.
 Method 2: Power off SIM7020 by AT command “AT+ C PO W D =1”.
 Method 3: over-voltage or under-voltage automatic power off. The function can be enabled by
AT command “AT+CBATCHK=1”. Default is disabled.
Note: For details about “AT+CPOWD” and “AT+CBATCHK”, please refer to Document [1].
These procedures will make modules disconnect from the network and allow the software to enter a
safe state, and save data before module be powered off completely.
The power off scenario by pulling down the PWRKEY pin is illustrated in the following figure.
(
Output
)
T
off
( Input
)
T
off(status)
UART Port
UndefinedActive
T
off(uart)
T
on
T
off-on
USB Port
Undefined
Active
T
off(usb)
PWRKEY
STATUS
Figure 8: Power off timing sequence
Table 9: Power off timing and electronic characteristic
Symbol Parameter
Time value
Unit
Min. Typ. Max.
T
off
The active low level time
pulse on PWRKEY pin to power
off module
0.8 1 - s
T
off(status)
The time from power-
off issue to STATUS pin output low
level(indicating power off )*
- - 0.5 s
T
off(uart)
The time from power-off issue to UART port off
-
-
1
s
T
off(usb)
The time from power-off issue to USB port off
-
-
1
s
T
off-on
The buffer time from power-off issue to power-on issue 5 - - s