MeiG_SLM550_Hardware Design Manual
MeiG Smart Technology Co., Ltd
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3.2 Pin definitions
Table 2 Pin description
Pin number
Pin number
I/O
Description
Comment
The power supply
VBAT
1, 2, 145, 146
I
The module provides Four
VBAT power pin pins. The
SLM550 operates from a
single supply with a voltage
range from 3.4V to 4.2V for
VBAT.
Externally, large
capacito-rs and
Zener diodes
must be added
for surge protec-
tion.
VBUS
141, 142
I/O
5V charging input power.
VCOIN
126
I/O
When the VBAT of the
system power is absent, the
external backup battery
provides power to the system
real-time clock.When VBAT is
present, the backup battery is
charged.
VCOIN pins
connect 3V
button batteries
or large
capacitors.
L15_1P8
111
O
1.8V power output, Power
supply always available for
IO port pull-up and level
conver-sion, not for
peripheral power supply
50mA
NC
125
L17_2P8
156
O
2.8V power output, used for
Sensor, TP power supply.
150mA
L20_2P85
129
O
2.85 V power output, for
LCD, Camera 2.8V.
300mA
SD_L21
38
O
TF card power supply pin
500mA
SD_L4
32
O
TF card signal pull-up power
supply pin
50mA
UIM1_VDD
26
O
UIM power supply pins
50mA
UIM2_VDD
21
O
UIM power supply pins
50mA
NC
193
GND
3, 7, 12, 15,
27, 51, 62, 69,
76, 78, 85, 86,
GND
