As shown in the following figure, most applications that use the DNA_PORTE2 primitive tie the DIN data input to a static value.
Figure 1. Shift In Constant
As shown in the following figure, the length of the identifier can be extended by feeding the DOUT serial output port back into the DIN serial input port. This way, the identifier can be extended to any possible length.
Figure 2. Circular Shift
It is also possible to add additional bits to the identifier using FPGA logic resources. As shown in the following figure, the FPGA application can insert additional bits via the DNA_PORTE2 DIN serial input. The additional bits provided by the logic resources could take the form of an additional fixed value or a variable computed from the Device DNA.
Figure 3. Bitstream Specific Code
