Associate III

Question

USB OTG HS Host in Mode FS internal PHY and USB OTG FS Device

Forum|Forum|12 years ago
January 15, 2014
11 replies
6730 views

Posted on January 15, 2014 at 19:14

I�m trying to use the STM32F407 as Host and Device simultaneously, my hardware configuration is the following:

-PA12, PA11, PA9 OTG FS as a Device

- PB14, PB15 OTG HS as a Host with Embedded PHY

If I define the preprocessor symbols:

USE_USB_OTG_HS and USE_USB_OTG_FS

The USB works ok as a Host, and the Device goes on and off, It seems that it is going to work but at the end the computer doesn't recognize it.

Also, I have tested defining just the preprocessor macro USE_USB_OTG_FS, and in this case the USB works well as a Device. I believe that the library is only implemented to work in HS or FS Mode

So, this is my question, Does any body has implemented USB as a device and host simultaneously using separated peripheral ? I mean i want to use the HS as Host with no external PHY and the FS as a Device.

#stm32f4 #usb #usb #usb #usb #stm32f407 #otg #host #host

This topic has been closed for replies.

chen

Associate II

Posted on January 16, 2014 at 12:38

Hi

''So, this is my question, Does any body has implemented USB as a device and host simultaneously using separated peripheral ?''

I do not think you can do this!

It is not possible (at least with the current USB specification) to have more than 1 host on the USB bus.

ie Why would you have the STM32 be a USB Host and a USB device at the same time?!?

It is common to have a Composite USB device - that is the STM32 behaves as multiple USB devices eg USB HID and USB CDC together at the same time.

The other alternative is called USB OTG - USB On The Go :

This allows a 'device' to switch between being a USB Host

(ie when the device is not connected to another host and a device is plugged into the STM32 USB)

and a USB device

(ie when the STM32 is plugged into a USB Host eg PC)

This is probably why you see :

''The USB works ok as a Host, and the Device goes on and off''

romybompartAuthor

Associate III

Posted on January 16, 2014 at 14:55

Thank you Chen_chung,

I would like connect for example: a keyboard or a mouse, and the same time send data to the computer when it is required.

Due to your answer I have new Questions:

1.- Can I configure the USB as a Device by default work with this until a condition that makes desinitialize USB, and then Configure the USB as a HOST ?

2.- How Can I implement the USB OTG with different port pins to be able to use Type-A and Type-B Connector at each port pits respectively ?

3. How would you implement this application.

chen

Associate II

Posted on January 16, 2014 at 15:20

Hi

''I would like connect for example: a keyboard or a mouse, and the same time send data to the computer when it is required. ''

This is not possible. The STM32 can only be a Host or a Device - it cannot do be both at the same time.

To connect to a Keyboard or mouse it must be a Host.

To connect to a host computer it must be a Device.

'' 1.- Can I configure the USB as a Device by default work with this until a condition that makes desinitialize USB, and then Configure the USB as a HOST ?''

Yes, that is what USB OTG is designed to do. However, it cannot be both at the same time, the STM32 must change over from being a device to host or visa vera.

''2.- How Can I implement the USB OTG with different port pins to be able to use Type-A and Type-B Connector at each port pits respectively ?''

No. The STM32 is only designed to have 1 USB port. This can be either a TypeA (normally for Host) or a TypeB (normally for device).

To connect the same port pins to both types of connector would be like connecting the USART port pins to 2x 9w D type - What do you think is going to happen when you connect 2 serial devices to the 1 port?

''3. How would you implement this application.''

What you ask is not possible - cannot be both Host and Device at the same time.

The only way to do it is to have 2 USB peripherals - one acting as a Host and one acting as target.

I do not think any of the STM32s range have 2 USB peripherals (but I have not really looked either)

From the sound of what you have done - you almost have the OTG part working.

You just have to make the switch between host/device work.

romybompartAuthor

Associate III

Posted on January 16, 2014 at 15:41

Ok Chen_Chung,

It is helpful. I will try to Implement the USB OTG. But You didn't answer my first question as I want, I mean, I probably can implement this hardware:

-PA12, PA11, PA9 OTG FS as a Device

- PB14, PB15 OTG HS as a Host with Embedded PHY

So by software I can Switch between one to other, Initialising the DEVICE (in pins PA12, PA11, PA9) at the first time and then with some hardware/software condition I can turn it Off (Deinitialize it). When it is turned off I will be able to configure the HOST in the other pins. Is it possible?

I have read from the Reference Manual that the STM32F407 has two peripherals: USB OTG FS and USB OTG HS, so what I believe is the USB peripherals can work independently once at time. Do I misunderstand the reference manual?...

Note: I have understood that I can't use both at the same time.

chen

Associate II

Posted on January 16, 2014 at 16:18

Hi

'' I have read from the Reference Manual that the STM32F407 has two peripherals: USB OTG FS and USB OTG HS, so what I believe is the USB peripherals can work independently once at time. Do I misunderstand the reference manual?... ''

Errm - Yes.

Maybe you can then. I was under the impression that there is only 1 USB peripheral but looking at the block diagram - they are indeed 2 separate peripherals a Full speed and a High Speed.

I do not know?!?. I have not tried it.

romybompartAuthor

Associate III

Posted on January 16, 2014 at 16:32

Great Chen_Chung.

I will try to do it. Because It is appropriate to use a type A connector and type B connector.

I will post my result.

Cheers.

billr1

Explorer

Posted on January 19, 2014 at 18:05

Bompart.Romy, please keep us updated on your progress. I am wanting to do exactly the same thing - one of the USB ports as host for keyboard or mouse and the other USB port for CDC device to talk to a PC.