USB mass storage host

[martindusek]

Hello,

is there anyone who managed to get USB mass storage host on Kinetis MCU reliably working?

I use Freescale USB stack 4.0.3 on bare metal K70. I managed to get working my USB host with most of sticks I have but I don't have the feeling that the application will work realiably.

I think kinetis USB host driver (khci_kinetis.c) is not written very well. I can see two main problems:

1) Changing CPU clock speed means that some sticks stops working with USB host.

2) Every transaction is once to 4 times nacked before the stick acknowledges it. I think it's a bug in driver, not problém of USB stick itself.

Is there any newer version of khci_kinetis.c?

Best regards

Martin

[BlackNight]

Hi Martin,

There is a new version 4.1.1 of the stack available on the Freescale USB stack site.

I'm using it with the KL25Z, but tried only a few memory sticks, and it works there.

But I have not looked into the details of transactions.

[martindusek]

Dear Erich,

thanks, but there are no big improvements in 4.1.1 khci_kinetis.c.

I made a simple test by adding time delay of 1000 ms before I send every WRITE10 command and the naking problem is exactly the same. Even USB stick has plenty of time to internally complete previous write command and to be ready to receive another one, it nackes 2 - 3 times when it receives next write command after 1000 ms. But actually, I'm not sure whether it is driver's or USB stick's issue.

The consequency is low speed write transfer.