Linux/AM5718: DDR HW interface query

SURESH p

Part Number: AM5718

Tool/software: Linux

In the AM5718 custom board bringing up, I have faced the Uboot not jump happened issue in both SD card & USB DFU modes (Applied some patch to enabled this feature in AM5718). During the analysis, i have found the DDR part A14 Row address signal not connected(NC). (Please refer below block diagram).

I suspect the Address line A14 is caused the Uboot not jump from SPL/MLO issue.Because the MLO/SPL can executed properly in our Custom board.

Custom board configuration Details:

Processor : AM5718
DDR3 : 1GB (Part ID: IS43TR16256A-125KBL-TR )
EEPROM : No EEPROM used
ROM : SD Card, eMMC

Could you please help me to figured it out this issue.

over 6 years ago

0 Brad Griffis over 6 years ago

TI__Guru*** 125430 points

The answer will be in the data sheet of the DDR IC. Look how many row address bits it has. Be sure you're looking at the right configuration because it usually changes depending on whether you've ordered a x8 or x16 variant of the part.

0 SURESH p over 6 years ago in reply to Brad Griffis

Intellectual 530 points

Hi Brad,

Thanks for your valuable response.

Actually the HW prototype have the x16 bit address DDR configuration & same DDR address configuration is used in U-boot too. So in this case the DDR_A14 signal is NC.

After i run the DDR test by put below code in SPL then i got the result as 0x20000000

DDR Test Code:

long RAMSIZE=0;
RAMSIZE= get_ram_size(0x80000000, 0x40000000);
printf("DDR RAM SIZE=[0x%X]\n",RAMSIZE);

So i conclude the DDR is valid up to 512MB address range because of the A14 signal is NC.

Note: The same Software can run in AM5718 EVK & it return 0x40000000.

0 Brad Griffis over 6 years ago in reply to SURESH p

TI__Guru*** 125430 points

FYI, I just made a correction to my original response. I meant to say ROW bits not column bits...

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Linux/AM5718: DDR HW interface query