Specifications

SIM7912&SIM7906 Hardware Design V1.02
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Pin name
Pin no.
I/O
Functional description
Comment
PWRKEY
2
DI
Power on/off the module,
active low
1.8V power domain.
Pulled-up internally.
Active low
The power on sequence is shown in the following figure.
PWRKEY
RESET_N
VBAT
T
on
Twait
VDD_EXT
T
1
USB Port
Undefined
Active
T
on(usb)
STATUS
T
on(
STATUS
)
UART
Undefined
Active
T
on(uart
)
Figure 10: Power on sequence
Table 10: Power on timing and electronic characteristic
Symbol
Parameter
Min.
Typ.
Max.
Unit
T
wait
The waiting time from power supply available to
power-on action
30
-
-
ms
T
on
The time of holding on PWRKEY pin to a low level
1000
-
-
ms
T
on(VDD_EXT)
The time from power-on action to VDD_EXT ready
100
-
-
ms
T
on(usb)
The time from power-on action to USB port ready
11
12
-
s
T
on(uart)
The time from power-on issue to UART port ready
15
-
-
s
T
on(STATUS)
The time from power-on action to STATUS ready
-
25
-
s
After enter force download mode, the PWRKEY pin need to release and don’t pull low always. If not,
the module will restart and then cause the download fail.
NOTE