i.MX6 SATA PHY. RTerm calibration resistor!

[martinchristian]

How to determine the value of (ResRef) RTerm calibration resistor on the SATA PHY?

On the "iMX6 Smart device system" the value is 191R 1%, why?

[martinchristian · Accepted solution]

Hi,

The closest I have come to a description of the resistor value, is found here:

Hardware Development Guide for i.MX 6Quad, 6Dual, 6DualLite, 6Solo Families of Applications Processors.

IMX6DQ6SDLHDG, Rev 1, 06/2013

Section 2.2 table 2-13

"SATA_REXT – Connect an external 191 Ω 1% resistor to GND."

"The impedance calibration process requires connection of this reference resistor.

If SATA is unused, the reference resistor may be populated if desired for manufacturability purposes, or left no-connect for cost savings."

/Martin.

[igorpadykov]

Hi Martin

from MX6DQ sect.54.1.4 Block Descriptions :

"RTerm Tuning -This block uses an external resistor (ResRef) as reference to

determine the proper calibration setting for centering the Rx and Tx termination

resistances at 50 ohms."

Best regards

chip

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[martinchristian]

Chip,

Yes this is correct, I also found this description in the Reference manual.
But nothing about what the value of the resistor should be... That is my question..

[igorpadykov]

Hi Martin

value you can find in i.MX6 SDP/SDB schematic

"MX6_SABRE_SDP_DESIGNFILES "

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=RDIMX6SABREPLAT&fpsp=1&tab=Design_Too...

Best regards

chip