STM32mp135f cust board ddr error

[guansonghuang]

hello，my custom board use the same ddr as STM32MP135F-DK board. but when I debug the example DDR_Init_A7.erro occus when verify data in address 0xc0000000 + 0x80。as show in picture.pls help me

[PatrickF]

Hi @guansonghuang 

with so little information, hard to give you best help.

Did you check the DDR supplies ?

Did the DDR routing done according to AN5692 DDR memory routing guidelines for STM32MP13x product lines (especially wire lengths and PCB impedance)

Any DDR signal connection mistakes (e.g. DQS, DM lines wrongly swapped, VREF, ZQ, etc...) ?

Any board soldering issue ?

Regards.

[guansonghuang]

1、DDR supply power is fixed 1.34v.

2、DDR routing reference en.stm32mp13x-series-ddr-memory-routing-guidelines-examples

3、this time I produce 2 boards(one is ok,and this one has this probrolem)

DDR range:0xc0000000 --->0xc0000000 + 0x80  is ok. so i think routing has no problem.but i could no understand why   0x80---->512M   have problem 

and DDR_TEST as follow:

[PatrickF]

Hi,

It seems clear that you have an issue with some DDR Address lines stuck to fixed level or short to something else. Maybe bad soldering somewhere. Check all DDR_Ax (and maybe DDR_BAx as well) path.

Did your assembly manufacturer do some checks after soldering ?

As issue is probably below one of the BGA package, an X-Ray analysis might be needed.

Regards.

[guansonghuang]

Hi

  From x-ray picture can not see solding problem clearly.

How can I confirm which DDR_Ax path has which kind of problem