AM5718: EMIF spreadsheet question

gorka mateo

Part Number: AM5718

Tool/software:

We are working on a design with an AM5718 processor and two DDR3L IS43TR16256BL-125KBLI memory modules.

We are running at 666MHz (1333MT/s). The memory partnumber Datarate is 1600MT/s. We are configuring the DDR Timigs of the spreadsheet as follows:

EMIF_RegisterConfig_GAMC_REV3_T_NEW _2.zip

We have a question about the tCKESR parameter. It appears in yellow. According to the memory datasheet, tCKESR = tCKEmin + 1nCK. In our case, 3 + 1 = 4. So it appears in yellow. Is this correct?

3 months ago

0 Karthikeyan S 3 months ago

TI__Genius 15480 points

Hi,

Based on tCK = 1 / fCK, tCK = 1.5 ns at fCK = 666 MHz. Could you try setting tCKESR = 4.5 ns (tCKESR = tCKE + 1ntCK = 3 + 1.5 ns) instead of 3 ns, and confirm if this resolves the yellow flag in the spreadsheet?

Regards,

Karthik

0 gorka mateo 3 months ago in reply to Karthikeyan S

Prodigy 40 points

You cannot set the value in ns only in tCK units. It has to be an integer. If we set it to 5 tCK, it turns green. Is it correct to add 1 additional tCK?

0 Karthikeyan S 3 months ago in reply to gorka mateo

TI__Genius 15480 points

Hi,

Yes, that’s correct one additional tCK must be added to tCKE when calculating tCKESR.

Regards,

Karthik

0 Gorka Mateo 3 months ago in reply to Karthikeyan S

Prodigy 40 points

Ok, but why is it necessary to add 1tCK? What is the reason?

0 Karthikeyan S 3 months ago in reply to Gorka Mateo

TI__Genius 15480 points

Hi,

According to the DDR3 specification,
tCKESR = tCKE + 1ntCK

Given:
fCK = 666 MHz

tCK = 1 / fCK
= 1 / (666 × 10^6)
= 1.5015 × (10^9)
= 1.5 ns

Therefore,
tCKESR = 3 + 1.5 = 4.5 ns

Since DDR timing parameters must be defined in integer tCK units,you can round up and add 5 tCK instead of 4.5 tCK

Regards,

Karthik

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AM5718: EMIF spreadsheet question