User manual

...the world's most energy friendly microcontrollers
2013-10-10 - t0014_0.21 11
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5.8 USB Micro-AB Connector
The EFM32GG-STK3700 board is equipped with a USB Micro-AB connector supporting USB Device
and Embedded Host modes. The figure below shows how the USB lines are connected to the EFM32.
The USB_VBUSEN line is connected to a current limited switch which supplies the VBUS line with 5V
when operating as a USB Host. The current limited switch also has a flag signal connected to the EFM32
which can notify it in case excessive current is drawn by the attached device. Note that the "J-Link" USB
cable must be inserted to provide 5V to the device when operating the EFM32 in host mode.
Figure 5.7. EFM32 USB Connector
USB OTG
Connector
PF11 (USB_DP)
PF12 (USB_ID)
PF10 (USB_DM)
PF6 (GPIO)
USB_VBUS
USB_VREGI
USB_VREGO
4.7uF1uF
VBUS Enable
5V
PF5 (USB_VBUSEN)
VBUS
D+
D-
ID
Overcurrent
5.9 Op-Amp Footprint
If the kit is flipped over there is a silk-print model of a typical operational amplifier feedback circuit. The
actual operational amplifier is one of the op-amps inside the EFM32. By soldering 0603 sized resistors
the EFM32 internal operational amplifier can be evaluated with exact resistor values.