I'm almost done with my customized circuit, relying heavily on the DM6467T EVM (actually Spectrum Digital HD 1080P EVM). The only memory in my circuit is the DDR and the NAND flash. My question unavoidably spans both hardware and software concerns, so it's important that I post it in this hardware-focused forum.
I just read section 4.4.2.4 paragraph 3 from the TMS320DM6467T datasheet (SPRS605B revised July 2010). The last sentence reads "Note: that either NOR Flash or ROM *must* be connected to the first EMIFA chip select space (EM_CS2). The EMIFA *does not* support direct execution from NAND Flash.
I have been advised elsewhere ( http://e2e.ti.com/support/embedded/f/356/p/66638/242389.aspx#242389 ) that I may want to develop my video analytics XDAIS routine using CE and FC on top of DSP/BIOS, and then possibly migrate to Linux after that in order to get some peripheral driver support. I have also been advised ( http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/99/p/63425/240626.aspx#240626 ) that complete systems can be written to run from NAND, including both kernel and filesystem.
(QUESTION: Is the following correct?) My understanding is that the DSP/BIOS or Linux OS is synonymous with the "kernel" mentioned above, and is found on the NAND (probably within the filesystem and located by boot code rooted to some fixed address in NAND). Also, CE and FC and my own XDAIS routine are elsewhere found in the filesystem. This all suggests that booting causes the OS and application code to get read from NAND... I presume into DDR2.
However, there's still that quote far above about "The EMIFA *does not* support direct execution from NAND Flash". QUESTION: Is this OK, and not a problem with the scenario above, which I believe is indeed *not* trying to execute directly from NAND.
QUESTION: With that said, is it indeed the case that all these things, OS+CE+FC+XDAIS must be small enough to fit in DDR2?
Now, there's still that quote far above that also reads "NOR FLash or ROM *must* be connected". QUESTION: What does this mean in my context? I don't have any NOR Flash or ROM in my circuit, and the post of the former link above implied I didn't need any.
QUESTION: Next, how do I program the NAND flash if it's soldered on my pcb?
Please note that the boss has not afforded me the opportunity to actually play with the EVM before designing my board. I must design the board first, then I can learn on the EVM while the board is being manufactured. We're on a very short timeline. I realize this is backward, but I have no choice.
One more thing. There are two procs, of course. The ARM and the DSP. QUESTION: Please confirm that the existence of the two procs can all get resolved later, within the context of the OS and other code, and still originating solely from my NAND. Surely this is true. If I can get the OS et al in DDR2 memory, presumably primary associated with the ARM, I think that allows the ARM to boot and load the application program on the DSP in turn.
