I'm working on my own streaming application (we're collecting high speed serial bitstream, converting it to parallel, and shipping it up USB).  We have an FPGA doing the serial->parallel conversion,  doing its own internal FIFOing, and feeding the FX2 slave interface as a master. (8 bit bus, synchronous--i think--, 40Mhz IFC clock sourced by the FPGA, SLWR pulsed when there's data to feed, etc).

When I use the cyconsole, my device shows up, reports my in end points, and is able to read 512 bytes when I do a bulk in.

I can write an application using CYApi to repeatedly do XferData() 512 bytes at a time.   My data stream is fast enough, however, that the FX2 fifo gets full and I'm forced to drop data. (I manage about 4MB/s)

So, I switched to overlapped IO (BeginXfer, WaitForXfer, FinishXfer) again with 512 bytes, and I can manage about 8MB/s, but I'm still being forced to drop data (we generate about 10MB/s).

So I started using large transfers (32KB, for example), at this point FX2/FPGA operate for a short time, and then would fall over and enter a stall state.  I don't know if this is normal or not.

I suspect this is when the FX2 FIFO becomes empty (which only happens when I'm transferring  enough data out of the system that I can drain the FX2 FIFO and the 4KB fifo on the FPGA) and I'm not doing something right at that point.  

TL;DR:   what can cause a bulk in endpoint in AUTOIN Slave FIFO mode to enter stall state?   I would have expected the endpont to NAK until data became ready, not stall.  (full disclosure, I haven't examined the USB bus, but when I get the URB stat after the pipe locks up it says stalled)

I can post the entirity of my slave.c and my win32 C simple streaming source code on monday when I get into the office.

 Please post your FX2LP project here.

 The data loss might occur if the rate at which your application is reading the data is not almost same as the rate at which you are pumping the data from FPGA.

You might want to to try and use Streamer application instead of your application, to see if there is a data loss.( Just change VID PID in streamer source code so that the Streamer application detects your device.)

Regarding why FX2LP is stalling the requests, looking into your firmware might help. So please post your code here.

Before that you might probably want to check if you are messing around with control and status register of IN end point in the firmware.

Thanks

Nikhil

 Also please post your OS specifications.

See if the below link helps you in any way:

http://msdn.microsoft.com/en-us/library/ff538112.aspx

Things seem to be working better today, but I'll post my code for posterity.

I started with AN61345, and used "slave_syncB".   Mostly, I modified it to have 2 bulk in endpoints (I'll be collecting data from two different sources and want to keep the data separated by endpoint), and changed the startup code to use my polarities, etc.

Attached to this message is my dscr.a51 file

 slave.c

 host streamer code (simple win32 console)

 hmmm, the descriptor file attachment didn't work:

 ok, apparently .a51 files can't be attached.

 ;;-----------------------------------------------------------------------------
;;   File:      dscr.a51
;;   Contents:  This file contains descriptor data tables.  
;;
;;   Copyright (c) 2003 Cypress Semiconductor, Inc. All rights reserved
;;-----------------------------------------------------------------------------
   
DSCR_DEVICE   equ   1  ;; Descriptor type: Device
DSCR_CONFIG   equ   2  ;; Descriptor type: Configuration
DSCR_STRING   equ   3  ;; Descriptor type: String
DSCR_INTRFC   equ   4  ;; Descriptor type: Interface
DSCR_ENDPNT   equ   5  ;; Descriptor type: Endpoint
DSCR_DEVQUAL  equ   6  ;; Descriptor type: Device Qualifier

DSCR_DEVICE_LEN   equ   18
DSCR_CONFIG_LEN   equ    9
DSCR_INTRFC_LEN   equ    9
DSCR_ENDPNT_LEN   equ    7
DSCR_DEVQUAL_LEN  equ   10

ET_CONTROL   equ   0   ;; Endpoint type: Control
ET_ISO       equ   1   ;; Endpoint type: Isochronous
ET_BULK      equ   2   ;; Endpoint type: Bulk
ET_INT       equ   3   ;; Endpoint type: Interrupt

public      DeviceDscr, DeviceQualDscr, HighSpeedConfigDscr, FullSpeedConfigDscr, StringDscr, UserDscr

;; TGE  DSCR   SEGMENT   CODE

;;-----------------------------------------------------------------------------
;; Global Variables
;;-----------------------------------------------------------------------------

;; TGE      rseg DSCR                 ;; locate the descriptor table in on-part memory.

            cseg at 100H               ;; TODO: this needs to be changed before release
DeviceDscr:   
      db   DSCR_DEVICE_LEN      ;; Descriptor length
      db   DSCR_DEVICE          ;; Decriptor type
      dw   0002H                ;; Specification Version (BCD)
      db   00H                  ;; Device class
      db   00H                  ;; Device sub-class
      db   00H                  ;; Device sub-sub-class
      db   64                   ;; Maximum packet size
      dw  0c410H                ;; Vendor ID
      dw   5486H                ;; Product ID (Sample Device)
      dw   0000H                ;; Product version ID
      db   1                    ;; Manufacturer string index
      db   2                    ;; Product string index
      db   0                    ;; Serial number string index
      db   1                    ;; Number of configurations

DeviceQualDscr:
      db   DSCR_DEVQUAL_LEN     ;; Descriptor length
      db   DSCR_DEVQUAL         ;; Decriptor type
      dw   0002H                ;; Specification Version (BCD)
      db   00H                  ;; Device class
      db   00H                  ;; Device sub-class
      db   00H                  ;; Device sub-sub-class
      db   64                   ;; Maximum packet size
      db   1                    ;; Number of configurations
      db   0                    ;; Reserved

HighSpeedConfigDscr:   
      db   DSCR_CONFIG_LEN      ;; Descriptor length
      db   DSCR_CONFIG          ;; Descriptor type
      db   (HighSpeedConfigDscrEnd-HighSpeedConfigDscr) mod 256 ;; Total Length (LSB)
      db   (HighSpeedConfigDscrEnd-HighSpeedConfigDscr)  /  256 ;; Total Length (MSB)
      db   1                    ;; Number of interfaces
      db   1                    ;; Configuration number
      db   0                    ;; Configuration string
      db   10100000b            ;; Attributes (b7 - buspwr, b6 - selfpwr, b5 - rwu)
      db   250                   ;; Power requirement (div 2 ma)

;; Interface Descriptor
      db   DSCR_INTRFC_LEN      ;; Descriptor length
      db   DSCR_INTRFC          ;; Descriptor type
      db   0                    ;; Zero-based index of this interface
      db   0                    ;; Alternate setting
      db   2                    ;; Number of end points 
      db   0ffH                 ;; Interface class
      db   00H                  ;; Interface sub class
      db   00H                  ;; Interface sub sub class
      db   0                    ;; Interface descriptor string index
      
;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Descriptor length
      db   DSCR_ENDPNT          ;; Descriptor type
      db   82H                  ;; Endpoint number, and direction
      db   ET_BULK              ;; Endpoint type
      db   00H                  ;; Maximum packet size (LSB)
      db   02H                  ;; Maximum packet size (MSB)
      db   00H                  ;; Polling interval


;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Descriptor length
      db   DSCR_ENDPNT          ;; Descriptor type
      db   86H                  ;; Endpoint number, and direction
      db   ET_BULK              ;; Endpoint type
      db   00H                  ;; Maximum packet size (LSB)
      db   02H                  ;; Maximum packet size (MSB)
      db   00H                  ;; Polling interval

HighSpeedConfigDscrEnd:   

FullSpeedConfigDscr:   
      db   DSCR_CONFIG_LEN      ;; Descriptor length
      db   DSCR_CONFIG          ;; Descriptor type
      db   (FullSpeedConfigDscrEnd-FullSpeedConfigDscr) mod 256 ;; Total Length (LSB)
      db   (FullSpeedConfigDscrEnd-FullSpeedConfigDscr)  /  256 ;; Total Length (MSB)
      db   1                    ;; Number of interfaces
      db   1                    ;; Configuration number
      db   0                    ;; Configuration string
      db   10100000b            ;; Attributes (b7 - buspwr, b6 - selfpwr, b5 - rwu)
      db   50                   ;; Power requirement (div 2 ma)

;; Interface Descriptor
      db   DSCR_INTRFC_LEN      ;; Descriptor length
      db   DSCR_INTRFC          ;; Descriptor type
      db   0                    ;; Zero-based index of this interface
      db   0                    ;; Alternate setting
      db   2                    ;; Number of end points 
      db   0ffH                 ;; Interface class
      db   00H                  ;; Interface sub class
      db   00H                  ;; Interface sub sub class
      db   0                    ;; Interface descriptor string index
      
;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Descriptor length
      db   DSCR_ENDPNT          ;; Descriptor type
      db   84H                  ;; Endpoint number, and direction
      db   ET_BULK              ;; Endpoint type
      db   40H                  ;; Maximum packet size (LSB)
      db   00H                  ;; Maximum packet size (MSB)
      db   00H                  ;; Polling interval

;; Endpoint Descriptor
      db   DSCR_ENDPNT_LEN      ;; Descriptor length
      db   DSCR_ENDPNT          ;; Descriptor type
      db   88H                  ;; Endpoint number, and direction
      db   ET_BULK              ;; Endpoint type
      db   40H                  ;; Maximum packet size (LSB)
      db   00H                  ;; Maximum packet size (MSB)
      db   00H                  ;; Polling interval

FullSpeedConfigDscrEnd:   

StringDscr:

StringDscr0:   
      db   StringDscr0End-StringDscr0      ;; String descriptor length
      db   DSCR_STRING
      db   09H,04H
StringDscr0End:

StringDscr1:   
      db   StringDscr1End-StringDscr1      ;; String descriptor length
      db   DSCR_STRING
      db   'C',00
      db   'y',00
      db   'p',00
      db   'r',00
      db   'e',00
      db   's',00
      db   's',00
StringDscr1End:

StringDscr2:   
      db   StringDscr2End-StringDscr2      ;; Descriptor length
      db   DSCR_STRING
      db   'A',00
      db   'B',00
      db   '-',00
      db   'U',00
      db   'S',00
      db   'D',00
      db   ' ',00
      db   'F',00
      db   'X',00
      db   '2',00
      db   ' ',00
      db   'G',00
      db   'P',00
      db   'I',00
      db   'F',00
      db   ' ',00
      db   't',00
      db   'o',00
      db   ' ',00
      db   'E',00
      db   'x',00
      db   't',00
      db   ' ',00
      db   'F',00
      db   'I',00
      db   'F',00
      db   'O',00
      db   ' ',00
      db   'E',00
      db   'x',00
      db   'a',00
      db   'm',00
      db   'p',00
      db   'l',00
      db   'e',00
      db   ' ',00
      db   'u',00
      db   's',00
      db   'i',00
      db   'n',00
      db   'g',00
      db   ' ',00
      db   'S',00
      db   'i',00
      db   'n',00
      db   'g',00
      db   'l',00
      db   'e',00
      db   ' ',00
      db   'T',00
      db   'r',00
      db   'a',00
      db   'n',00
      db   's',00
      db   'a',00
      db   'c',00
      db   't',00
      db   'i',00
      db   'o',00
      db   'n',00
      db   's',00
StringDscr2End:

UserDscr:      
      dw   0000H
      end

 Now that that's all attached, I am able to send a lot of data, but occasionally it will stall (like very occasionally, and I have no idea what causes it).  I haven't checked for data integrity, but none of the win32 calls failed and I was able to transfer multiple terabytes over several hours.

When it does stall, the call to WaitforXfer() returns false, and then the next FinishDataXfer returns false as well.

The NtStatus and USBR status after WaitforXfer is 0, but "STALLED" when it returns from the failed FinishDataXfer.

I will say that the FPGA I'm using (Microsemi ProAsic3 starter kit) and the Daleda Dl380C ez-usb development board is a VERY noisy environment, so it might be the cause of the instability.

 Exact error code when it happens:

Ntstatus:   0x00000000 [[state=SUCCESS status=USBD_STATUS_SUCCESS]]

UsbdStatus: 0x00000000 [[state=SUCCESS status=USBD_STATUS_SUCCESS]]

Ntstatus:   0xc0000120 [ [state=STALLED status=UNKNOWN]]

UsbdStatus: 0xc0010000 [ [state=STALLED status=UNKNOWN]]

And it seems like it happens when I do things on my PC (like open projects, or web pages with java, etc), but not always.

I've tried adding '->Reset() and/or ->Abort()' but neither of those seem to clear the bad condition on the USB pipes appropriately.  I always seem to need to quit my daemon and reset my FX2/FPGA contraption to get data moving again.

.