Honored Contributor
Honored ContributorHi Dave,
No, option bits are bits that are placed in a completely different range of the flash. The location of the option bits must be entered via the PFL MegaWizard and is then compiled into the PFL source code. When the PFL runs it will go read the option bits from flash (mine are located at address 0) to determine which flash configurations (0..7) are programmed and supposedly valid. Since I have already programmed both the user and factory configurations via JTAG/MAXII/PFL the option bits will contain an address+valid pair for the flash range 0 (blocks f to f+38) and flash range 1 (blocks u to u+39) where f and u are the base block numbers used for the factory and user configurations, respectively. FvM mentioned back in 2010 that the PFL puts a 4 byte header at the front of the data. This supposedly contains the PFL version required to read the data as well as the length of the configuration data: http://www.alteraforum.com/forum/showthread.php?t=22312 (http://www.alteraforum.com/forum/showthread.php?t=22312) Also, I just found this thread which exactly describes what I am seeing: http://www.alteraforum.com/forum/showthread.php?t=28657 (http://www.alteraforum.com/forum/showthread.php?t=28657) I will continue struggling with this tomorrow... /John.
