09-20-2011 11:01 AM
Hello everyone,Would this be possible: I want to connect the dedicated parallel 512 Mbit Flash for AP-Configuration. Additionally I would like to connect two 128 Mbit serial Flash memories. For Configuration I want use only the parallel memory. In user mode I would like to use the two serial Flashes and some address ranges of the parallel flash for storing pictures. This address ranges would be tristaded during configuration. Is this plan realistic? If not, do you have another idea? I want to configure with AP. But in addition I want to store pictures non-volotile with at least 256 Mbit. My problem is, I have very less pins free on my Cyclone III Thank you very much in advance! Best regards, Christopher
09-20-2011 05:25 PM
Christopher,According to the Cyclone III Handbook, you can use AP configuration and have access to the flash in user mode. If some of the address lines are tri-stated during configuration, can you guarantee that you will be accessing the correct location in flash? Is this a limitation of the PFL when connecting the Cyclone III directly to a standard flash device rather than a configuration device? Would pull-downs be appropriate? What is driving you to AP mode? Can you use AS with a config device and the parallel flash for storing pictures? As Dr. Bogatin says, sometimes an okay answer now is better than a good answer later. Hope this is an okay answer. Regards, Scott
09-21-2011 07:47 AM
well, my plan was to use only a few address lines for configuration. Configuration data doesn't need much memory capacity.The other address lines, I would use for fetching pictures out of the flash during user mode. So the FPGA thinks, there are two memories. Perhaps Pull-Downs aren't necessary, because of the tri-state status of the adress pins for the pictures during user mode. I don't know, if this is possible according to the locations of the addresses in the flash during configuration. Parallel configuration is necessary, because I need a very short configuration time.