[AN65974] Why the PMODE is configured as output and set to b11 in slaveFIFO2b_fpga_top.v

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SePo_2528491
Level 1
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5 replies posted First solution authored First reply posted

It  creates this hassle described in the app note:

   
    

The FX3 DVK should be programmed before programming the Xilinx FPGA board. The FX3 DVK will not enumerate on the host PC if the FPGA has already been programmed, because it drives the PMODE lines

   
   

I don't want to disconnect the FPGA each time I program FX3, can simply I change the PMODE to be the input? 

   
    

input[1:0]  PMODE;  

    

 

    

 

   
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1 Solution
Anonymous
Not applicable

Just changing PMODE pins on the FPGA side won't help.

   

When the FX3 powers up, the PMODE pins needs to be as per the F11 for usb boot. So, you can  do it by using hardware pull-ups, or you need to drive the PMODE pins to have the same voltage and logic levels as F11 using FPGA.  So, the FPGA can output these lines and drive the voltages on FX3's PMODE pins while the boot.

   

Please let us know for any question

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2 Replies
Anonymous
Not applicable

Just changing PMODE pins on the FPGA side won't help.

   

When the FX3 powers up, the PMODE pins needs to be as per the F11 for usb boot. So, you can  do it by using hardware pull-ups, or you need to drive the PMODE pins to have the same voltage and logic levels as F11 using FPGA.  So, the FPGA can output these lines and drive the voltages on FX3's PMODE pins while the boot.

   

Please let us know for any question

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SePo_2528491
Level 1
Level 1
5 replies posted First solution authored First reply posted

Thanks a lot Nishant, it helped. I just cut the pins off  and now I can configure FPGA and load FX3 independently. 

   

   

 

   

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