USB connection

ezrab · ‎2011-01-18

Posted on January 18, 2011 at 11:08

USB connection

tsuneo · ‎2011-05-17

Posted on May 17, 2011 at 14:21

> i see that it is possiable to connect the USB with external PHY and without.

What is the target MCU?

There are a couple of variations of external PHY (or transceiver)

a) External USB transceiver for isolation

- PIC18F/24F/32, etc

An isolator is inserted between the MCU and the transceiver

b) OTG transceiver

- NXP LPC family

OTG transceiver does OTG-specific protocol on the bus (SRP, HNP)

These MCUs work as an embedded host or device without OTG transceiver

c) UTMI/ULPI for high-speed

- OMAP

etc.

Tsuneo

ezrab · ‎2011-05-17

Posted on May 17, 2011 at 14:21

i am using the stm32f207zg. i see it has internal usb PHY. why use external?

tsuneo · ‎2011-05-17

Posted on May 17, 2011 at 14:21

> i am using the stm32f207zg.

Are you talking on this figure on the STM32F205xx/207xx datasheet?

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00237391.pdf

Figure 81. OTG HS connection dual-role with external PHY

It's a ULPI PHY for high-speed OTG.

STM32F2xx has on-chip high-speed USB host and device engine. They work as just an embedded host or just an device, but not for OTG without the external ULPI PHY.

Tsuneo