i.MX28 EMI_DDR_OPEN

[chris321]

Hello Community,

I've a question for routing the EMI_DDR_OPEN trace. If I read this right the appnote AN4215 says DDR_OPEN route length equals CLK routed length + DQS routet length. But there are 2 CLK traces (CLK and CLKn) and 4 DQS (DQS0, DQS0n, DQS1, DQS1n).

Do that mean I have to sum up the matched length of DQS and the matched length of CLK?

For Example_

DQM0 = 17,1 mm

DQM0n = 17,2 mm

DQM1 = 16,9 mm

DQM1n = 16,8 mm

CLK = 11,9mm

CLK = 12,1mm

Is now the length of EMI_DDR_OPEN (17+12)mm ?

thank You

[chris321]

Thank you jimmychan,

I asked this question because I wondered that this formula doesn't work in the i.mx28 Design Files.

On this board I've measured:

CLK 12,3mm,

DQS0 17,4mm and

DQS1 17,1mm

with an EMI_DDR_OPEN = 35,6mm

[jimmychan · Accepted solution]

Yes, you are right.