AM4378: USB2.0 speed configuration

g.f.

Part Number: AM4378
Other Parts Discussed in Thread: AM4372

Hi,

I have a question about AM437x USB(Host).

My customer want to fix the speed of USB to HighSpeed or FullSpeed or LowSpeed.
We are checking the AM437x TRM but can't find any register details.

From AM437x TRM(spruhl7g) page.2536 "16.1 Introduction,
it seems that we need NDA to get more information.
So, should I contact to my local TI FAE?

Or if there are any information about setting USB to fixed speed, please tell me.

best regards,
g.f.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

Yes, AM437x USB documentation access is restricted. See this thread for details: e2e.ti.com/.../601660

0 g.f. over 8 years ago in reply to Biser Gatchev-XID

Guru 15520 points

Hi Biser,

Thank you for the reply.
I understood that we need NDA for getting more information.

By the way, does existing Linux USB driver support the commands
which can fix the speed of USB2.0 from the termimal(ex.TERATERM)?

best regards,
g.f.

0 Bin Liu over 8 years ago

TI__Guru**** 168631 points

g.f. said:

I have a question about AM437x USB(Host).

My customer want to fix the speed of USB to HighSpeed or FullSpeed or LowSpeed.
We are checking the AM437x TRM but can't find any register details.

The AM437 USB host is a xHCI controller, which doesn't have a register bit to control the speed, as far as I know. The speed is determined by the enumeration negotiation.

0 g.f. over 8 years ago in reply to Bin Liu

Guru 15520 points

Hi Bin,

Thank you for the reply.
I understood.

By the way, does USB(Device) have register bit to control speed?Or is it same as USB(Host)?

best regards,
g.f.

0 Bin Liu over 8 years ago in reply to g.f.

TI__Guru**** 168631 points

Yes, you can force the speed for USB device mode. Please search for 'maximum-speed' in arch/arm/boot/dts/am4372.dtsi, you can override it in your board dts file.

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AM4378: USB2.0 speed configuration