topic Re: USB DMA request fails in Vybrid Processors

USB DMA request fails

dirkschmitt — Tue, 28 Jul 2015 05:29:41 GMT

Hi all,

currently we have problems with usb dma. If I read data with the cpu from the receive buffer of the usb dma, while the usb dma stremas data into it, the received data are corrupted.

My questions are:

What is the priority of the usb dma transfer on the ahb bus?

I started to read the doc of the NIC301 and I saw that there are QoS values which refelcts the priority of the bus masters. How can I check these

Qos values and where can I modify these?

-> Info on 07/29/2015: I found out that the data cache is enable for the RX Buffer. But in the MQX driver code the data ache lines of the

rx buffer are flushed before the dma request is started. It seems to me that the flushing of the data cache line is not sufficient in this case?

Thank you,

Dirk

Nachricht geändert durch Dirk Schmitt

Re: USB DMA request fails

alejandrolozan1 — Mon, 10 Aug 2015 19:10:58 GMT

Hi,

As far as I have seen the priorities of the NIC remain the same and do not change.

You can get access to the NIC registers via:

#define NIC301_BASE_PTR ((NIC301_MemMapPtr)0x40008000u)

Which MQX version are you using? I know that latest release solved a few issues.

Best Regards,

Alejandro

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