Increase the amplitude of the USB D+, D-

[javierw]

Hi,

I am using the IMX6 dual-lite. 

We had test out the eye diagram.

The test supplier recommended that we increase the amplitude for the D+, D- at IMX6. 

Is there any software method to achieve this result? 

Thanks!

[gusarambula]

Hello Javier Wan,

It is possible to increase the D+/D- amplitude buy changing the termination resistors. There is more explanation of this on Application Note 4589 (link below)

Configuring USB on i.MX 6 Series Processors

http://cache.nxp.com/assets/documents/data/en/application-notes/AN4589.pdf

There are several alternatives which allow for small adjustments. For example, you may change the high-speed driver current using the USBPHYx_TXn[D_CAL] bits. You can find a bit more on this alternative on the AN4589 and the specifics of this register in section 66.3.2 of the i.MX6Q Reference Manual (link below)

http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX6DQRM.pdf

I hope this helps!

Regards,