RM48 USB Host

Hello Griswald,

Please refer to the wiki page: http://processors.wiki.ti.com/index.php/HALCoGen_USB_Device_-_driver_%26_CDC_Class.

You will find this example useful.

Best regards,
Diwakar

Diwakar,

Actually, that's exactly the opposite of what I'm asking about.

Regards,

Griswald Brooks

Hi Griswald Brooks,

At Present i am working on same. Is there any drivers provided?.

Regards,

Narasimha

Griswald,

Yes, I've used the USB host stack provided by Micrium in order to run the USB signal quality tests.

TI does not provide a USB host stack but the USB host is an OHCI standard host and many OS vendors like Micrium can support you.

Nope. Never found any.

Griswald,

Hi do you mean you never found any OS vendors that support the RM48 USB Host?

Or did we cross pass on our replies...

A little more information to set the background.

"Driver" code examples for the USB host peripeheral can be found in the standard doc:

ftp://ftp.compaq.com/pub/supportinformation/papers/hcir1_0a.pdf

In case you wanted to roll your own.  I've actually in the past worked with the code examples in that doc to do some hardware testing and with a few adaptations it worked fine.

However, this just gets you very primitive capabilities.  You need a stack to sit on top of this to manage the bus, enumerate devices, connect devices to device drivers, and schedule bus traffic.   To give an analogy, this would be like the TCP/IP stack is to an Ethernet driver.  The TCP/IP stack is a significant middleware component.  Similarly a USB host stack goes well beyond the scope of a driver for the OHCI controller.

I would say the good thing we did with RM48 is to use an OHCI standard controller which makes getting 3P support easier than it would if we had a custom controller.

I never found a freely available USB host stack for the RM48.

Regards,

Griswald Brooks

Hi Griswald,

Ok, I agree.  I'm not aware of any free USB host stacks for OHCI outside of the linux world.

But they exist commercially, and considering the complexity of such a package the commercial options are probably a good value.   It's probably worth getting a price quote to put a number to so you can properly assess before trying to build your own USB host stack.

We had gotten a price quote, ...and it was considerable. LUFA provides a stack for Atmel devices which was ported for NXP and I believe the Stellaris library provides a USB host stack (though I have not extensively researched the Stellaris Host stack).

Regards,

Griswald Brooks

Griswald,

The NXP parts seem to have an EHCI host controller which would either have a full speed OHCI or UHCI controller embedded in it;  so probably it wouldn't be a huge effort for you to port this to work with the RM48 product.  I don't know if you are legally allowed to do this given NXP's license - you'd need to make that determination.

LUFA looks like it's an Atmel employee so not sure he'd port for you if you asked but you could always try.

It did look like there might be limitations in terms of the number of simultaneous devices you could support - I saw something to that effect on the NXP page but I didn't study it closely.   I don't believe you'll find that with a stack from a commercial vendor - at least they tend to allow you to configure the memory resources the stack uses to match the available memory and the number of devices (and hubs) that you might want to attach to the USB host port.  Something else you might consider depending on what you need.  

We do not have support for the TI RTOS (ex. the Stellaris library I think merged into this) and it's associated stacks with the RM48 product.   Mainly because our investments in software for the RM48 product are around products that could be safety certified.   

We had tried porting the NXP library and it turned into a very large effort, lasting several months that we eventually had to give up on. It does not support multiple devices nor USB hubs.

Just for the sake of knowing, does Stellarisware when used with the TM4C come with a USB Host stack?

Regards,

Griswald Brooks

Hi Griswald,

I haven't used TI-RTOS which was released this year.  It seems to have replaced Stellarisware.  As I mentioned, we do not have this available for Hercules (and don't plan to have availble ... of course things may change) because of the safety criteria.

But according to this page:  http://www.ti.com/tool/ti-rtos

TI RTOS comes with a significant amount of middleware one being TI-RTOS USB which according to the page was formerly part ot Stellarisware.  So that might answer your question.

If you're thinking of using a Tiva part in order to get USB functionality this could work.  

If you're considering porting this software TO Hercules - I don't think the host controller on Tiva is an OHCI host.  You might have more luck porting from one of the Sitara products but all I know that is freely available there is linux based code.