STM32F21xxx
Application block diagrams
Figure 84. USB OTG FS (full speed) host-only connection
GPIO
GPIO+IRQ
STM32F20xx
VDD
EN
Overcurrent
Current limiter
power switch(1)
5 V Pwr
OSC_IN
OSC_OUT
PA9
PA11
PA12
VBUS
DM
DP
VSS
ai17296c
1. The current limiter is required only if the application has to support a VBUS powered device. A basic power
switch can be used if 5 V are available on the application board.
2. The same application can be developed using the OTG HS in FS mode to achieve enhanced performance
thanks to the large Rx/Tx FIFO and to a dedicated DMA controller.
Figure 85. OTG FS (full speed) connection dual-role with internal PHY
VDD
5 V to VDD
voltage regulator (1)
GPIO
GPIO+IRQ
EN
Overcurrent
VDD
Current limiter 5 V Pwr
power switch(2)
STM32F20xxx
OSC_IN
OSC_OUT
PA9
PA11
PA12
PA10
VBUS
DM
DP
ID(3)
VSS
ai17294c
1. External voltage regulator only needed when building a VBUS powered device.
2. The current limiter is required only if the application has to support a VBUS powered device. A basic power
switch can be used if 5 V are available on the application board.
3. The ID pin is required in dual role only.
4. The same application can be developed using the OTG HS in FS mode to achieve enhanced performance
thanks to the large Rx/Tx FIFO and to a dedicated DMA controller.
Doc ID 17050 Rev 8
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