USB low-full-high speed peripherals Forum Discussions

Hi All

I am creating an application to stream video data over the EZ USB FX2LP and display it on the PC. I have implemented an MPEG reader using cypress ez usb firmware example AN58069 . I am currently using the USB Control center and I have run into an issue where in if I do mutiple data transfers I miss a lot of data packets while I can do on complete data transfer successfully.  I want to continuously writ data to a file and read that file using another application to display video and I am not sure how to do that as i will have to make mutiple read coomands in which case I will end up mising a lot of packets. So I was not sure how to perform continous reads on the slave fifo using a PC application. Any examples for this would be helful.

Dear all,

This is a puzzling question we can't figure out.

We use FX2LP family (CY7C68013A) since a long time (10 years) in BULK mode to transfer blocks of 2048 bytes in Hi Speed and I never had big problems while computers were evolving. During the last months I am having a lot of problems with laptops because it seems that transfer is often unsuccessful.

To be precise, I had the chance to observe this problem on two different pc ASUS with these specs: controller usb Intel xHCI, s.o. Windows 10, processor Intel i3

The data to transfer are took from a FIFO using the GPIF interface according to a typical mechanism of "clock and read, clock and read...".

The weird thing is that it GPIF waveform has a strange behavior (see attached files) when the transfer is unsuccessful. The attached file are the two waveforms of a same "flag output" that I use to trace when the GPIF starts reading (flag goes high) and when it finishes reading (flag goes low). As you can see when the transfer is unsuccessful there is a longer reading cycle in the middle (sometimes are more than one).

Additional information about the driver: we have used WinDriver (Jungo) for many years and now we tried WinUSB (Microsoft).

Here is the configuration of the endpoints. I have tried to configure them also both 512x4 and both 1024x2 but same result.

;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Length of this descriptor = 7 bytes
      db   DSCR_ENDPNT         ;; Descriptor type = Endpoint
      db   01H               ;; Endpoint number, and direction (01H = EP1, out)
      db   ET_BULK             ;; Endpoint type
      db   40H               ;; Maximun packet size (LSB)
      db   00H               ;; Max packect size (MSB) --> 64 bytes
      db   00H               ;; Polling interval (in # of frames. Ignored for Bulk and Control EPs)
;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Length of this descriptor = 7 bytes
      db   DSCR_ENDPNT         ;; Descriptor type = Endpoint
      db   81H               ;; Endpoint number, and direction (81H = EP1, in)
      db   ET_BULK             ;; Endpoint type
      db   40H               ;; Maximun packet size (LSB)
      db   00H               ;; Max packect size (MSB) --> 64 bytes
      db   00H               ;; Polling interval (in # of frames. Ignored for Bulk and Control EPs)

SYNCDELAY;
EP2CFG = 0xAA; // b7=1 (valid)
// b6=0 (dir OUT: PC -> Periph)
// b5=1 (BULK)
// b4=0 (BULK)
// b3=1 (size 1024)
// b2=0
// b1=1 (buffering 2x)
// b0=0 (buffering 2x)
SYNCDELAY;
EP6CFG = 0xE0; // b7=1 (valid)
// b6=1 (dir IN: PC <- Periph)
// b5=1 (BULK)
// b4=0 (BULK)
// b3=0 (size 512)
// b2=0
// b1=0 (buffering 4x)
// b0=0 (buffering 4x)

Thank you

HI everyone, I want to ask off for a problem.Under the android 5.1.1  use cypress 6801 chips, communication mainly use cyusb lib library, but the device communication always cyusb_bulk_transfer function returns -7 when the status value. I want to consult everybody, this is what causes.  thank you !

  If the master wants to send a stream of data whose length is not a multiple of 512, the last packet is not be automatically committed to USB because it is smaller than 512 bytes. To commit that last packet, the master can do one of two things: It can pad the packet with dummy data in order to make it exactly 512 bytes long, or it can write the short packet to the FIFO, then pulse the PKTEND pin.

  But how to pad the packet with dummy data.