How to implement DE0 SDRAM as 2-port RAM

--- Quote Start ---

sdram timing analysis

The "KEY TIMING PARAMETERS" table has the relevant details. It says speed grade -5 when operated at a CAS latency of 3 has a minimum guaranteed operating frequency of 200MHz, but when you operate it with a CAS latency of 2 the minimum guaranteed operating frequency is 133MHz. You can interpret the other columns similarly. If you look at the package marking on the ISSI RAM on your board, you'll likely find that it has a -7 speed grade marking.

--- Quote End ---

Mine appears to be a -6 (see image attachment). That seems to imply that the sdram_controller clock needs to be 166MHz if the CAS latency cycles setting is set to 3. Do you agree?

I still don't know which clock, the sdram_controller clock or the SDRAM_CLK out to the chip is supposed to be delayed. (Fine tuning how much it is delayed comes later). To try to answer that question, as you suggested, I attempted to look at the QSYS project you mentioned again since I edited the original compilation:

synth.tcl compiles but in qsys_system you don't use a pll so that doesn't answer the question about the two different sdram clocks.

qsys_system.tcl doesn't compile: "Error:can't find package qsys exactly 14.0"

synth_qsys.tcl compiles but doesn't seem to do anything relevant. The qsys project file is the same as before. still no PLL.

The other tcl files don't seem relevant to answering the question.

So, that's done. Now would you be able to tell me which of the two clocks (the sdram_controller clock and/or the SDRAM_CLK out to the chip) is supposed to get the -3ns delay? I know it needs to be tuned with TimeQuest but a starting point would be nice.

A second, more important issue, is whether or not the SDRAM chip is even fast enough to process 640 x 480 x 30fps x 2 (read + write) = 18,432,000 random read/write operations every second. Even at 100,000,000Hz you would think there would be plenty of time but maybe not with all of those other delays, pre-charges, etc going on.. Are 18.5 million random operations a second too much in your opinion?