USB On-The-Go on MCF51JM128 hardware connections

[juanoxoby]

Hi,

I'm doing a research project where I use a Coldfire MCF51JM128 processor. Using a Bluetooth-USB dongle, I'm planning to connect a wireless PS3 controller. In the processor's datasheet I get these two different connections:

The second one seems to be the one I need for my application because is the OTG one. The question is: I must route that circuit in my board? Including those comparators and 3-states?

[TomE]

> I'm doing a research project where I use a Coldfire MCF51JM128

> processor.

Did you have to use this chip and development board?

> Using a Bluetooth-USB dongle, I'm planning to connect a wireless PS3 controller.

It might be possible to get that working, but it might take a long time.

Is the purpose of the Research Project is to demonstrate how hard it is to get this connection working, or are you hoping to use the connection to demonstrate something else with the PS3 controller?

If the latter, then try to get an already working system to start with. Type "interfacing ps3 controller" into Google and see what others have done already.

The reason Bluetooth and USB work so easily on a PC is all the huge amount of software work written specifically for the PC. It is very difficult to make it look that easy. Just getting USB Master-side software working reliably on an embedded processor is a big job. The best start is to use a device that is running Linux because most of the drivers have already been written for the hardware.

Again, unless you want to use the one port to connect to devices and to a PC and to other likeminded devices, you don't need or want OTG.

Tom

[JimDon]

Take a look at this schematic that implements an OTG interface:

http://cache.freescale.com/files/soft_dev_tools/hardware_tools/schematics/EVB51JM128SCH.pdf

You will have to figure out how to talk to the blue tooth dongle at the hardware level, then figure out how the Blue Stack works above that.

After that you can figure out how to talk to the PS3 controller.

[TomE · Accepted solution]

The safest way to get a working hardware design is to start with a working development board or kit.

Once you get that kit working with your software and hardware, copy all of the development board schematics that are relevant to your application.

This has the advantage that you don't have to understand the hardware design :-)

Don't ever try to design hardware from the Data Sheet and Reference Manuals. They are always incomplete. The only "working references" are the Development Boards.

If you can't buy a development kit, download the manuals and schematics for them and copy the design.

Are you sure you need OTG? That's a way to make a USB port that can act as  a controller (so you can plug a mouse or USB key or USB/Serial adaptor into your device) and also then make your device act like a HID or USB Key or serial port to a different computer. If you only want the device to act like a "client" then you don't need the complexity of OTG.

OTG also makes the USB software in the device more complicated.

Read up about OTG here:

http://en.wikipedia.org/wiki/USB_On-The-Go

Tom