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 arbitrary 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. Programmable Device Image (PDI) Specific Code
