I am using the Slave FIFO to do bulk transfers from the host to an FPGA. When I send a packet from the host I am able to read the expected number of bytes from the Slave FIFO. However instead of the expected data I get an alternating sequence of bytes. Further, there are 2 sequences, which alternate with each packet sent.

For example:

And so on.

The endpoint is double buffered, so maybe it switches between sequences when the buffer changes?

I verified with a USB analyzer that the packet sent to the FX2LP is correct.

 Any ideas why I get these symptoms?

 Hello,

In which mode are you using FX2LP ? Auto / Manual mode ? If in manual mode, are you not committing the FIFOs from FX2LP (inside 8051 firmware) ? Also if in manual mode, have you not armed the buffers initially (inside TD_INIT() ) ? If you can attach your code (TD_INIT and TD_POLL ), we can take a look, if something os missing.

Regards,

Gayathri

I am using auto-mode.

After looking in detail at other forum posts I found one which seems to have similar symptoms. A post near the end indicates that the poster is getting alternating values.

However no answer is found. Maybe there is a tech support case related to the other thread?

http://www.cypress.com/?app=forum&id=167&rID=50953

Link to thread reference in previous post...

SLOE is always asserted in our design (Master does not have control over this pin in our design). Is this ok?

TD_INIT:
      SYNCDELAY; BREAKPT &= ~bmBPEN;      // to see BKPT LED go out TGE
    // set the CPU clock to 48MHz
       SYNCDELAY; CPUCS = ((CPUCS & ~bmCLKSPD) | bmCLKSPD1);   


    SYNCDELAY; IFCONFIG = 0xC0;   // use IFCLK pin driven by internal logic
                         // for now don't enable slave fifo
                         // fifo pins conflict with spi programming for fpga   

      
   
    SYNCDELAY; REVCTL = 0x00;     // DYN_OUT=0, cpu bypassed for out packets 
    SYNCDELAY; EP1OUTCFG = 0xA0;    // see TRM section 15.14
   
    SYNCDELAY;  EP1INCFG  = 0xA0;
          

    //disable other endpoints
    SYNCDELAY; EP2CFG = 0x7f;
    SYNCDELAY; EP8CFG = 0x7f;
    SYNCDELAY; EP6CFG = 0x7f;
   

    SYNCDELAY; EP4CFG = 0xA0;     // sets EP8 valid for OUT's
                         // and defines the endpoint for 512 byte packets, 2x buffered
   
    SYNCDELAY; FIFORESET = 0x80;  // reset all FIFOs
    SYNCDELAY; FIFORESET = 0x02;
    SYNCDELAY; FIFORESET = 0x04;
    SYNCDELAY; FIFORESET = 0x06;   
    SYNCDELAY; FIFORESET = 0x08;   
    SYNCDELAY; FIFORESET = 0x00;
     
   
    SYNCDELAY; EP4FIFOCFG = 0x10; // this lets the EZ-USB auto commit OUT packets
                       // and sets the slave FIFO data interface to 8-bits
   
    SYNCDELAY; EP2FIFOCFG = 0x00;     //set all fifocfg to 8 bit interface so portd works     
    SYNCDELAY; EP8FIFOCFG = 0x00;     
    SYNCDELAY; EP6FIFOCFG = 0x00;
     


    SYNCDELAY; PINFLAGSAB = 0x00; // define all flags as indexed            
    SYNCDELAY; PINFLAGSCD = 0x00;        
   

    SYNCDELAY; PORTACFG = 0x00;   // used PA7/FLAGD as a port pin, not as a FIFO flag    
    SYNCDELAY;     FIFOPINPOLAR = 0x12; // set sloe active high, set empty == 1

   EZUSB_InitI2C();
   Initialize_Timer();

   EA = 1;                          // Enable 8051 interrupts
   I2CTL = bm400KHZ;
  
   ////////////////////////////////////////////////////////
   // Initialize Port D IO as SPI signal pins (SPI Flash Chip store FPGA code)
   // We need this for Write/Read to SPI chip for FPGA reprogramming.
   InitializeSPI();

   /////////////////////////////////////////////////////////
   // Reset FPGA register
   // Just to hold FPGA in reset  
   FPGA_REG_RESET_PORT    |=  FPGA_REG_RESET_REG_BIT;        // High - Reset FPGA
  
   // Fetch data from SPI and send to FPGA
   g_FPGA_Alive = FpgaCfgSerialMode(SVID_FPGA_BIN_SIZE);       

   MillisecondDelay(500);
   FPGA_REG_RESET_PORT    &= (~FPGA_REG_RESET_REG_BIT);    // Low  - out from reset
   MillisecondDelay(500);
 
   EA = 0;

   OEB = 0;
   SYNCDELAY; IFCONFIG = 0xCB; //enable slave fifo mode

TD_POLL:

      empty...

 Hello Dan,

Can you post the TD_INIT() part of your code ? since FX2LP is in Slave, AUTO mode, I believe there is no code in your TD_POLL (). Please confirm. 

Regards,

Gayathri

 Hello imwood,

From the code that you had pasted, I could see that the endpoint configuration that you are using is not valid. The endpoint configuration that you should be using, should be one among the 12 valid configurations as is mentioned in section "1.18 EZ-USB Endpoint Buffers" in EZ-USB TRM. Please refer and correct the same. Then double check if it is working.

(Are you also having issue similar to what Dan had posed above ?)

Regards,

Gayathri

i am working with dan on the same cypress project. Thanks, I will take a look at the endpoint configurations....

Thank You!

The end point configuration was the issue...

The problem is solved.

that was the problem. I commented out these lines and it started working. Thanks!

    //disable other endpoints
    SYNCDELAY; EP2CFG = 0x7f;
    SYNCDELAY; EP8CFG = 0x7f;
    SYNCDELAY; EP6CFG = 0x7f;

 Hello Dan, imwood,

Glad to hear that the problem is resolved now, and thank you for posting the solution here. It might help someone later.

Regards,

Gayathri