USB bulk transfers (Host requests handling)

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Linas on Thu Sep 27 07:41:52 MST 2012
I am working with LPC1769. I am trying to workout USB bulk transfers (IN and OUT endpoints handling).

Once Host first issues (IN request) I can't get any data. No interrupt is set (debugging with LPCXpresso).
In case Host issues (OUT request) I got interrupt and my BulkOut function is called.

Host IN requests starts working in case my BulkOut(void) functions includes USB_WriteEP(IN, data, 64). Then
IN requests starts working and BulkIn function is called.

LibUsb drivers are used for PC application.

What are the solutions and causes? Maybe I have missed something.

void BulkOut(void) {

  //Read data from Host
  numBytesRead = USB_ReadEP(BULK_EP_OUT, &BulkBufIn[0]);
  //In case I include here USB_WriteEP() BULK_IN interrupts starts working.


void BulkIn(void) {

  //Write data to Host
  USB_WriteEP (BULK_EP_IN, &BulkBufOut[0], 64);


Best regards,