iMX6Q USB client full-speed eye-diagram issue

Tony1z · ‎01-27-2016

Hi Sir,

We designed our board with iMX6Q and measured USB client full-speed eye-diagram.

The USB signal voltage level in full-speed cannot reach 3.3V. USB traces impedance is 90 ohm differential controlled.

We tried to increase amplitude with setting register USBPHY1.TX.D_CAL=0x0 by memtool.

The amplitude of full-speed USB signal increase a little but still cannot reach 3.3V. It only has around 2.6V amplitude. (Refer to attached bmp file)

Any other software suggestion ?

igorpadykov · ‎01-28-2016

Hi Tony1z

available software configuration is given in AN 4589

Configuring USB on i.MX 6 Series Processors sect.4.3.3 Operational settings

If this does not help, it is necessary to look at hardware methods for improving

signal quality.

Best regards

igor

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