USB Bulk Reads via Cypress EZ-USB FX2

How have you established that?

What parameters do you use to call the driver function?

We tested a different device with it's own firmware. The program used to load the .HEX file into the device memory, (r)enumerate USB devices and issue vendor requests etc was still the same.

This setup worked fine and so therefore the problem was not with the host end of things.

Well, here's the function call:

r = usb_bulk_read(hCurrent_reader, 0x86, buffer, USB2_BUFFER_SIZE, 1000); if (r != USB2_BUFFER_SIZE){ printf("Bulk Read failed (%d).\n",r); printf("%s\n",usb_strerror()); } else { printf("Bulk read success\n"); }

You may almost certainly require more specific information; if this is so then please ask.

Thank you, Gavin Brewer.

I use IOCTL_EZUSB_BULK_READ instead of usb_bulk_read(), but I suppose the functionality is similar. There are two ways the read can fail:

A) If you supply a buffer that is smaller than the amount of data that is in the active FX2 FIFO, the read will fail with an error. I don't know the usb_bulk_read() function, but maybe it returns a negative value in this case. Check the docs.

B) If the FX2 has less data in the active FIFO than the size of your buffer, the read will complete but return only the number of bytes actually read. In this case the read has not completely failed, but your code will claim so.

Hope this helps, Marc