Users Manual Part 1

SIM8260A_Hardware Design_V1.05
www.simcom.com 36 / 122
The power on sequence is shown in the following figure.
Figure 12: Power on sequence
Table 14: 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
100
-
-
ms
T
on
The time of holding on PWRKEY pin to a low level
2
-
-
s
T
1
The time from power-on action to VDD_EXT ready
-
11.45
12
ms
T
on(usb)
The time from power-on action to USB port ready
-
20
-
s
T
on (STATUS)
The time from power-on action to STATUS ready
-
55
-
s
V
IH
Input high level voltage on PWRKEY pin
1.1
-
2.1
V
V
IL
Input low level voltage on PWRKEY pin
0
-
0.3
V

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.

The timing of T
on(usb)
and T
on (STATUS)
is related to the module software. The time here is based on
the standard version test and is for reference only.
3.2.2 Power Off
The following methods can be used to power off the module.
●
Method 1: Power off the module by holding the PWRKEY to a low level two second then release.
●
Method 2: Power off the module by AT command “AT+CPOF”.
NOTE