AM437x with LPDDR2

Tsutomu Furuse

Other Parts Discussed in Thread: TIDEP0024

Hi.

Would please advise me on the following LPDDR2 issue?

One of my customer is developing a AM437x board with LPDDR2. The board is working fine with LPDDR2 @133MHz. However it is frozen sometimes with LPDDR2 @266MHz. The customer is referring to the AM437x standard GEL files obtained from the following Wiki page, to configure the LPDDR2.

http://processors.wiki.ti.com/index.php/OMAP_and_Sitara_CCS_support#AM437x

The customer is using Micron MT42L256M32D2LG-18WTA. Since TI's TIDEP0024 reference design uses MT42L256M32D2LG-25WT, the difference is speed grade only. "-18" means 533MHz clock rate and "-25" means 400MHz clock rate. The customer's one is faster than TI's one. If TI's GEL works for TI's TIDEP0024, I assume that the customer can use the GEL as it is.

The board (@266MHz LPDDR2 clock) passes the DDR test in the GEL, but fails the EDMA test in the GEL.

Best regards,
Tsutomu Furuse

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

What is your main oscillator frequency? There has been a similar issue reported for AM335X, where it turned out that the board tested had a different main oscillator frequency than the one set in the GEL file: e2e.ti.com/.../1583579

See also this wiki for AM437X EMIF settings: processors.wiki.ti.com/.../AM437x_DDR_Configuration_and_Programming_Guide

0 Tsutomu Furuse over 8 years ago in reply to Biser Gatchev-XID

Expert 1435 points

Biser,

Thank you for the information.

The oscillator frequency is 25 MHz. I think it is not a problem. TI's GEL reads the CTRL_STS (SYSBOOT[15:14]) register to check the oscillator frequency. TI's TIDEP0024 reference design also use 25 MHz oscillator.

Best regards,
Tsutomu Furuse

0 Biser Gatchev-XID over 8 years ago in reply to Tsutomu Furuse

TI__Guru**** 393215 points

Another thing to consider is that their part is a different speed grade. This is very likely to require changes in the EMIF timing registers. The "AM43xx_DDR_register_calc_tool.xls" Excel sheet should be used to derive the correct timing values. It can be downloaded from the wiki link given by me above.

0 Tsutomu Furuse over 8 years ago in reply to Biser Gatchev-XID

Expert 1435 points

Biser,

Thank you for the info.
I introduced the customer to the Wiki page you shown.

Best regards,
Tsutomu Furuse

0 Vladimir Melnikov over 7 years ago in reply to Biser Gatchev-XID

Prodigy 40 points

Hello Biser

Could you please insight me how to open design files

in

file included in zip archive is .DSN and cann not be opened by the Viewer that is proposed by "Get Viewer" link

0 Biser Gatchev-XID over 7 years ago in reply to Vladimir Melnikov

TI__Guru**** 393215 points

.DSN files are OrCAD schematics. There is also a PDF version of the schematics on this page.

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AM437x with LPDDR2