Description

In 5 and 6 series Virtex FPGA,  when performing a "Verify" or "Readback" operation on external SPI flash, the DINSPI port of the STARTUP primitive is used to output the readback data to the FPGA fabric. Why there is no DINSPI port in the STARTUP primitive of  a 7 series device?

Solution

The DIN pin is dedicated in 5 and 6 series Virtex FPGA, but is dual-purpose in 7 series.

So after configuration, you can set the DIN to an input (or inout), it can read SPI's DATA port directly and then forward the readback data into the FPGA fabric.