DDR3 leveling procedure (code or algorithm)

Todd Squires

Other Parts Discussed in Thread: AM3352, AM3358

Hi All,

I'm bringing up a board based on the AM3352, using a DDR3. The board is using a custom boot loader, and my dev system is entirely Linux. The DDR3 appears to be working reliably at 303MHz even though I've not yet worked out the optimum PHY timing values. Regardless, I won't feel comfortable until I've gone through that step.

To that end, I found the web page "AM335x DDR PHY register configuration for DDR3 using Software Leveling", however the procedure given there involves CCS (which I'm currently not using). For my development process, it would be simpler if I could just grab the source code which performs this step, and build it in my environment. Does TI make this code available? If not, is there a detailed (register level) description of the algorithm it performs? I'm happy to write the code myself, but none of the doc I've found so far gives me quite enough detail to do that.

Thanks.

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Todd,

The linked GEL file on the wiki page is C-code. You can open it with any text editor.

0 Todd Squires over 12 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Hi Biser,

Thanks for the quick reply. I had found that file previously (AM3358_StarterKit.gel), but it didn't look to contain the actual ratio search code (I see some init, and some RAM tests in there, but none of the search). To see if the search code was available on the Internet, I googled for some of the text output it generates, namely, I searched for this:

"The Slave Ratio Search Program Values"

That didn't turn up any source, so I figured the code wasn't any place obvious.

Yesterday, after reading some of the other posts here, I realized I could perform this test just by changing the ratio values, and doing a quick RAM test. That way I could work out what the minimum and maximum values were for each value, and pick a value in the center of each range. I wrote some code, and made it iterate until it converged on a set of values. Seems to work pretty well. So at this point, I think I'm in good shape, although please let me know if you see problems with that approach.

0 Biser Gatchev-XID over 12 years ago in reply to Todd Squires

TI__Guru**** 393215 points

Well, if it works for you then fine. Maybe you should create a thorough RAM test after you have finalized your values. And then of course, booting the Linux kernel successfully is the ultimate test.

0 Todd Squires over 12 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Hi Biser,

Indeed. I've had a RAM test running all night, and everything looks healthy so I'm probably good to go. The kernel is next on my to-do list. :-)

Thanks for your help.

0 Biser Gatchev-XID over 12 years ago in reply to Todd Squires

TI__Guru**** 393215 points

Sounds good. If you have more boards of the same batch, you might also test them with the final values to confirm your results..

0 Todd Squires over 12 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Will do.

It's good to know TI is so responsive on the forums, as I'm sure I'll have some other questions before too long.

Thanks again.

0 sivakumar parameswaran over 12 years ago in reply to Todd Squires

Prodigy 195 points

Hi Todd,

Could you please share the c code you wrote for DDR3 software leveling. I have hard time to get my custom board with optimum DDR3 phy value.

I tried the DDR3_slave_ratio_search_auto.out file given by TI and it didnt work well.

Thanks

siva.

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DDR3 leveling procedure (code or algorithm)