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Explorer
Explorer
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Registered: ‎11-23-2013

When does the FPGA begin to configure??

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Hello,

 

I use xc7k325 in my design and Vivado 2014.1. The configuration mode was SPI and the flash was N25Q128. Bank 0, Bank14 and Bank15 are all 3.0V.

 

I can successfully program the FPGA and the flash. But it seems the flash didn't been load successfully.

 

I doubt the power sequence between FPGA and flash cause the problem. The DS182 gives the Tpor, but it didn't say when the FPGA begin to load bitstream from the flash---after all power rails become stable or other times??

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Scholar
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Registered: ‎02-27-2008

Re: When does the FPGA begin to configure??

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c,

 

The configuration starts when the Vccint, Vccaux, and Vcco (for the config bank) are all sensed as being greater than their trip points, and a timer has counted to a terminal count (the power on circuit attempts to guess at when the power rails will be stable and within specifications).

 

You can measure when configuration starts by observing the INIT_b, and the other signals.

 

Check the mode pins.  Check that the flash has the proper contents.

 

Austin Lesea
Principal Engineer
Xilinx San Jose

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Registered: ‎02-27-2008

Re: When does the FPGA begin to configure??

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c,

 

The configuration starts when the Vccint, Vccaux, and Vcco (for the config bank) are all sensed as being greater than their trip points, and a timer has counted to a terminal count (the power on circuit attempts to guess at when the power rails will be stable and within specifications).

 

You can measure when configuration starts by observing the INIT_b, and the other signals.

 

Check the mode pins.  Check that the flash has the proper contents.

 

Austin Lesea
Principal Engineer
Xilinx San Jose

View solution in original post

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Registered: ‎11-23-2013

Re: When does the FPGA begin to configure??

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Hello austin,

 

Thank you!

I don't know how to "check that the flash has the proper contents". Does it means there is something wrong with the configuration of the ".bin" files?

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Registered: ‎02-27-2008

Re: When does the FPGA begin to configure??

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c,

 

Well, the correct format has to be used, so the device is able to understand the configuration it is reading.

 

It sounds like you are able to configure using the JTAG.  That is good, and is a first step.  Putting that configuration into the flash memory is then the next step.

 

http://www.xilinx.com/support/documentation/sw_manuals/xilinx11/pim_c_introduction_indirect_programming.htm

 

http://www.xilinx.com/support/documentation/sw_manuals/xilinx11/pim_p_configure_spi_bpi_through_fpga.htm

 

XAPP586

 

All things you should be reading...

Austin Lesea
Principal Engineer
Xilinx San Jose
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