Feature request: SDRAM driver

[VladisM]

CPU need access to larger data space. This space can be provided by external SDRAM. We need to write SDRAM driver for IS42S16160B that is located on DE0 nano board.

SDRAM datasheet: IS42S16160B.pdf

[VladisM]

This project look really interesting. It have nice SDRAM driver that I probably can use. Also, this project use makefile to compile VHDL design. This can be great inspiration!

There are also links related to this SDRAM driver:
https://hamsterworks.co.nz/mediawiki/index.php/SDRAM_Memory_Controller
https://hamsterworks.co.nz/mediawiki/index.php/Simple_SDRAM_Controller

It's look like all these drivers using single clock domain. I will have to write clock domain crossing or speed up CPU to 100MHz.

[VladisM]

Started working at speed up CPU core to simplify SDRAM driver implementation.

[VladisM]

It's look like driver mentionet abow is able to run with 50MHz without problems. (CPU is able to run at 50MHz now)

[VladisM]

there is also one interesting driver:
https://github.com/stffrdhrn/sdram-controller

[VladisM]

Work on sdram driver started in pull request #21.

[VladisM]

branch deleted; this approach was completely wrong; i will start from scratch