Usb Interface - Quectel SC200L-EM Hardware Design

SC200L Hardware Design
A reference design for the battery charging circuit is shown below.
Figure 9: Reference Design for Battery Charging Circuit
Mobile devices such as mobile phones and handheld POS systems are powered by batteries. When
different batteries are utilized, the charging and discharging curve has to be modified correspondingly so
as to achieve the best effect.
If the thermistor is not available in the battery, or adapter is utilized for powering the module, then there is
only a need for VBAT and GND connection. In this case, the system may mistakenly judge that the battery
temperature is abnormal, which will cause battery charging failure. In order to avoid this, VBAT_THERM
should be connected to GND via a 10KΩ resistor. If VBAT_THERM is unconnected, the system will be
unable to detect the battery, making the battery cannot be charged.
VBAT_SNS pin must be connected. Otherwise, the module will have abnormalities in voltage detection,
as well as an associated power on/off and battery charging and discharging issues.
The SC200L series module supports current-type current meter by default, and conducts current
sampling through a 20 mΩ sampling resistor R2.

3.8. USB Interface

SC200L contains one integrated Universal Serial Bus (USB) interface which complies with the USB 2.0
specification and supports high speed (480Mbps) and full-speed (12Mbps) modes. The USB interface is
used for AT command communication, data transmission, software debugging and firmware upgrade.
The following table shows the pin definition of the USB interface.
SC200L_Hardware_Design
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