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USB Superspeed Peripherals

New Contributor

I am trying to modify the slave fifo example to output the clock on gpio[16] instead of receiving the clock. I changed the direction in the GPIF II Designer, and when I diff the header file output, I get: 

   
85c85 <     0x800003B0,  /*  CY_U3P_PIB_GPIF_CONFIG */ --- >     0x80000380,  /*  CY_U3P_PIB_GPIF_CONFIG */
   

When I probe the pin, however, there is no clock running. I am guessing I need to set some other registers up to pipe the clock out?

   

How do I output the gpif clock on gpio[16]?

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6 Replies
Anonymous
Not applicable

Hi,

   

FX3 GPIF II needs to be configured as master if you want it to drive clock or address.

   

You can do that if you don't have to sample address in your state machine.

   

Please let me know if you need any more details from me.

   

Thanks,

   

sai krishna.

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New Contributor

In slave fifo mode on the FX2, the clock could be configured as an an input or an output. We used it as an output so that we did not have to have additional clocks on the PCB.

   

I hoping that I can do the same with the FX3. I want the slave fifo functionality to stay exactly the same other than the clock is taken from the FX3 core and put out on the pin. Is this possible?

   

I am not sure I understand your comment regarding the address. I would still like the address bus to be inputs.

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Anonymous
Not applicable

Hi,

   

I tested it today and I am getting the clock (close to 100MHz) out of GPIF II.

   

I did not do any changes other than changing the direction of clock from external to internal.

   

Please find the attached header file that I generated after changing the clock direction of the Slave FIFO interface.

   

Thanks,

   

Sai Krishna.

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New Contributor

 Hmmm.... I tried your gpif file and I am not seeing a clock. Can you post your .c file as well so I can compare my code with your other function calls?

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Anonymous
Not applicable

Hi,

   

Please find the attached .c file.

   

May be you should change the PIB clock division to 4.

   

/* Initialize the p-port block. */
    pibClock.clkDiv = 4;

   

Thanks,

   

Sai Krishna.

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New Contributor

 OK. I got it working. Thanks.

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