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UM1871

Hardware layout and configuration

2.8

USB OTG HS

STM32446E-EVAL evaluation board supports USB OTG high speed communication via a

USB Micro-AB connector (CN8) and USB HS PHY USB3300 (U4).The evaluation board can

be powered by this USB connector (CN8) at 5V DC with 500 mA current limitation. USB

power switch (U3) is connected on VBUS and provides power to CN8 (if SB131 is closed).

Green LED LD7 will be lit when either:

•

power switch (U3) is ON and STM32446E-EVAL works as a USB host

•

VBUS is powered by another USB host when STM32446E-EVAL works as an USB

device.

Red LED LD10 will be lit when over-current occurs.

JP22 should be configured as explained in Table 5: Boot0 and Boot1 related jumpers.

2.9

RS232 and IrDA

The RS232 transceiver U8 (with hardware flow control CTS and RTS) connected to D-type

9-pins RS232 connector CN25, and IrDA transceiver U10, are connected to USART1 of

STM32F446ZET6, which can be also shared with ST-LINK USART.

The signal Bootloader_RESET (shared with CTS signal) and Bootloader_BOOT0 (shared

with DSR signal) are added on RS232 connector CN8 for ISP support.

USART1 selection is done by setting JP6 and JP8, refer to Table 8: RS232 and IrDA related

jumpers for detail.

Table 8. RS232 and IrDA related jumpers

Jumper

Description

JP8

RS232_RX output of RS232 transceiver is connected to PA10 (USART1_RX in

conjunction with JP4), when JP8 is set as shown below (default setting):

IrDA_RX from IrDA transceiver is connected to PA10 (USART1_RX in conjunction

with JP4) when JP8 is set as shown below:

USART_TX from ST-LINK is connected to PA10 (USART1_RX in conjunction with

JP4) to support virtual com port when JP8 is set as shown below:

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