On Friday, October 20, 2006 9:50 AM Ben Warren wrote:
Of course you don't have to use the SPD stuff, but you should.
[Leonid] Unfortunately SPD stuff is out of question - on our board UDIMM's EEPROM is not connected to CPU I2C bus.
If the BDI won't work as-is, you need to learn more about your DDR controller and your particular DIMM's timing information, both of which should be readily available. While DDR control is fairly complicated, there aren't that many knobs to turn and you may get lucky early on.
[Leonid] That what I'm going to do. I have datasheet, the module name is MT8VDDT12832U. If somebody from this community happens to have BDI or u-boot configuration for such or similar module, I'll appreciate that information.
Another approach that's less systematic is to get U-boot working, dump the DDR controller register contents and use those in your BDI config file.
[Leonid] I'm familiar with this method - I used it to get BDI work with some ARM board. Yet as you said I must have u-boot working with this DIMM first and provided I don't have SPD option it will probably require exactly the same effort as BDI configuration - configure all registers properly manually.
This will involve a few painful workspace-less flash burns, though... You can save a bit of pain by stripping your U-boot image
to
bare-bones.
[Leonid] It's not that bad actually - takes less than 2 minutes to burn entire 512KB u-boot image together with flash erasing even without workspace. But as I see now I may as well concentrate on BDI config file - exactly same registers must be configured - without touching u-boot code at all for the time being.
Sorry there's no easier answer, but if your hardware is wired right you'll probably nail this quickly.
[Leonid] I do appreciate your help, thanks a lot.
Regards, Leonid.