• State Not Answered
  • Locked Locked
  • Replies 24 replies
  • Subscribers 21 subscribers
  • Views 5089 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

LPC1769 USB DMA Mode

Shaunak Shilimkan

Hi,
I am currently using IN EP3 of the LPC1769 to realize Isochronous transactions to the Host. I have configured the this endpoint in the DMA mode

 LPC_USB->EpDMAEn   = 0x80;

I enable the DMA on the EP when I receive the Set Interface command from the Host. However, I see that the EpDMAEn does not change its value to 0x80 as desired (this could probably be because the register is Write Only, but I am not sure).
Please can someone let me know the conditions under which the DMA mode for the EP would get disabled?

In order to get around this problem I write to the above register everytime I create a DMA Descriptor. Is this a good method? Many time we end up loosing bytes of information on the host but I am not sure if it is actually because of this.

Any help in this regard would be much appreciated.

Thanks very much.

Regards,
Shaunak

0