MeiG_SLM320_Hardware Design Manual
MeiG Smart Technology Co., Ltd
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3.5 Start up
3.5.1 PWRKEY Pin boot
When the SLM320 module is in shut down mode, the module can be turned on by pulling down the
PWRKEY for at least 1s. It is recommended to use an open set drive circuit to control PWRKEY pin. The
reference circuit is as following:
47K
4.7K
≥
500ms
Turn on pulse
PWRKEY
Figure 6 Open set drive reference boot circuit
Another way to control the PWRKEY pin is through a push button switch. A TVS is placed near the
button for ESD protection. The reference circuit is shown as below:
Close to S1
TVS
PWRKEY
S1
Figure 7 Button startup reference circuit
The boot sequence is shown in the figure below
:
V
IL
≤
0.3V
V
H
1.6V
VBAT
PWRKEY
≥
500ms
RESET_N
STATUS
(OD)
I nactive
Active
UART
I nactive
Active
USB
≥
2.5s
≥
10s
≥
13s
VDD_EXT
2 ms
NOTE
≥
≥
Figure8 Power-on sequence diagram