HSUSB Reset Timing

[mjbcswitzerland]

Hi

The HSUSB host has automatic reset timing that the users doesn't look to have any control over:

Normally hosts assert the reset for 10ms but I measure 55ms when the HSUSB asserts it.

A) A FS device reference connected to a PC

B: The same FS device connected to the i.MX RT that issues the reset command on detection

PORTSC1 |= (USBHS_PORTSC1_PR);

This is not an issue with the device being reset but is this quite large deviation from the standard 10ms time intentional?

Regards

Mark

[Hui_Ma]

Hi Mark,

Long time no see.

I did a test with my PC to connect FRDM-KL27Z OpenSDA (FS device) and get below result:

When I use RT1060EVK board running <host_msd_fatfs_bm> demo with FRDM-KL27Z OpenSDA FS device with below enumeration info:

Could you let me know which RT SDK USB host example you are using? 

Thanks for the attention.

Mike

[mjbcswitzerland]

Hello Mike

I see a reset of 54ms in the first recording but none in the second.

Are you sure the first is the reset from the PC since it is about the value I see from the i.MX RT?

I am measuring with a product developed with the uTasker USB Host stack but I will repeat soon with an SDK demo to see whether it has the same time or not.

Regards

Mark

[Hui_Ma]

Hi Mark,

Yes, I did the same test again with my PC connects with FS device got the same result:

Reset: 54ms.

Below is the transfer info:

Thanks for the attention.

Mike

[mjbcswitzerland]

Hi Mike

Apart from the fact that I expect the PC to reset 10ms (which I usually measure,but it can vary) the fact that you measure 54ms (I measured 55ms) for the i.MX RT host reset time means that we both can verify that the i.MX RT host reset pulse is about 54m and not the expected 10ms.

The question remains why it is 55ms and not 10ms as is suggested in the user's manual !!

Regards

Mark

[Hui_Ma]

Hi Mark,

When I use RT1060 evaluation board to connect USB FS device get below enumeration process:

There without USB bus reset procedure.

Do you have the same behavior on your site when using MCUXpresso SDK provided USB Host demo?

best regards,

Mike