Kinetis MicrocontrollersのトピックRe: Cancelling USB Transfers

Cancelling USB Transfers

chuckh — Mon, 24 Feb 2014 23:48:03 GMT

I have added a timeout in my code to make sure that my data being sent out on the BULK_IN pipe finishes in a certain time. If it doesn't, I want to abort the transfer (aka flush it from the pipe). I've tried using the USB_DCI_Cancel_Transfer/_usb_device_cancel_transfer() function, but that ooesn't seem to work properly. I would expect that once I call that function, the g_winusb_endpoint_data.ep[index].bin_consumer and g_winusb_endpoint_data.ep[index].bin_producer would once again be equal. I don't think that is the case.

What is the proper way to flush my pipe from my device? Do I need to reset the endpoint somehow?

Thanks.

Re: Cancelling USB Transfers

chuckh — Tue, 25 Feb 2014 00:33:55 GMT

I've found that this works. Any reason not to do this?

//Use this to cancel any outgoing USB transfers on a given pipe

uint8_t WinUsbClearSendPipe( uint_8 controller_ID, uint_8 ep_num)

{

uint8_t status = USB_DCI_Cancel_Transfer(controller_ID, ep_num, USB_SEND);

//Attempt to cancel transfer and update the consumer pointer

if(status == USB_OK)

{

uint8_t index = USB_Map_Ep_To_Struct_Index(controller_ID, ep_num);

g_winusb_endpoint_data.ep[index].bin_consumer++;

}

return status;

}

Re: Cancelling USB Transfers

CarlosCasillas — Mon, 03 Mar 2014 22:13:49 GMT

Hello Chuck,

If the implementation is based on a consumer-producer scheme, it seems to be a valid procedure, just considering that the data that was previously stored on the buffer will not be deleted until overwriting it with a new transaction.

Anyway, if you are implementing a custom application, you could refer to the precompiled examples included on the installation folder, and compare how the transfers are managed.

Hope this will be useful for you.
Best regards!
/Carlos

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