Layout of customer have a mistake about GPANAIO to GND. (default must be a no connect)
We found GPANAIO information about this output is reserved for Freescale manufacturing use on table 2-14 in IMX6DQ6SDLHDG.pdf.
We are not sure it has any side effect on i.MX6 chip, if the pad connect GND.
We use DDR stress test tool via USB OTG and result run start calibration fail.
(Other customer's i.MX6 board use the same DDR parameters could run pass over 600MHz)
Could you have explain and any suggestion?
Thanks a lot,