Unmatch about DDR DDR Output Driver Average Impedance for i.MX53

[ko-hey]

Hi all

I have questions about DDR calibration resistance in Output Driver Average Impedance for i.MX53.

As it mentioned in following thread, the Table 43-2 and 43.3.454 unmatched and we have same question.

But there didn't answer the thread.

https://community.nxp.com/thread/328744

Q1.

Table 43-2 does not describe the DSE value when it set DDR3 dde_sel = 01.

Refer to 43.3.454 IOMUXC_SW_PAD_CTL_GRP_DDR_TYPE and it is explained as "NVCC_EMI_DRAM = 1.5 V +/- 5% (DDR 3), ddr_sel = '' 01: 160 Ohm '

In the case of dde_sel = 01 setting of DDR3, is the value of DSE the same as DDR_SEL = 01/11 of LPDDR 2 mode in Table 43-2 ?

Q2.

If Q1 is not same, could you provide a DSE value when it set DDR3 dde_sel = 01 ?

Q3.

We think that the calibration resistance which is shows in yellow line is wrong.

Because there are no settings in Table 43.3.454.

The correct calibration resistance is 200 Ohm. Am I correct ?

Ko-hey

[igorpadykov · Accepted solution]

Hi Ko-hey

>Q1.2

please refer to below description

>Q3

correct is 240 Ohm

Best regards
igor
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[TomE]

The table you quote lists resistances of 240, 120, 80, 60, 48, 48 and 34.

In the thread quoted from the original post in this thread, I pointed out the above values are wrong and gave corrections. That was back in August 2014. I had to look in the i.MX6 manual to get the correct values (which are 48 and 40).

i.MX53 Reference Manual Errors, is there a list? 

I would suggest the original poster do the same. When in doubt, read a newer manual for a different product.

In the above thread, four years ago, gusarambula reported these bugs, but said it might take "some time" for these to be fixed. He also said these postings are likely to be the only places you'll see these sort of corrections.

Tom