problem to initialize ddr3 connection to P1022

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problem to initialize ddr3 connection to P1022

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Contributor I

Hi,

I start to bring up card with P1022.

DDR chips are discrete., and I have one bank of ddr3 with 32 bits width. (two chips with X16 width)

The initialize process failed.

I see the ddr clock is not running.

I have one memory bank with two pairs of clock for two chips. one clock pair for every chip. is it a problem??

both clock pairs didn't run.

I check all the setup option and read the status of the configuration of the DDR.

I couldn't find problems.

pls. advise

Regards

Zeev Gerber

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NXP TechSupport
NXP TechSupport

MCK should appear as soon as at least one DDR_CSn_CONFIG[CS_n_EN] is set.

> I have one memory bank with two pairs of clock for two chips. one clock pair for every chip.

> is it a problem??

Yes.

Write leveling normal operation is not guaranteed in this case because of violation of the following requirement:

AN3940 - Hardware and Layout Design Considerations for DDR3 SDRAM, Table 1. DDR3 designer checklist, 46:

"Ensure one clock pair is used for each chip-select. The clock pair should follow the address/command/control signal groups in fly-by topology."

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Contributor I

Hi,

I make the timing constraints for every chip so it's should meet the timing requirement.

current problem is that after the dram setup, which include set the cs to bank number #1, the two pairs of mck didn't run.

pls. advise

Zeev gerber

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NXP TechSupport
NXP TechSupport

Use a debugger to check that DDR_CSn_CONFIG[CS_n_EN]=1 and GUTs_DDRCLKDR=0x00000000.

Use a scope to ensure that all supply voltages are applied correctly.

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