My customer is now doing USB eye diagram measurement on i.MX6Solo.
According to i.MX 6 Series USB Certification Guide(Document Number: IMXUSBCGUG), the USBPHYx_TXn register should be 0x1c060607, which meas that TXCAL45DP/DN and D_CAL use the default value.
But my customer found that when USBPHYx_TXn was set to 0x1c060607, the eye pattern was bad. So they tried some other values, and finally they found that value of 0x1C020003 was OK for their eye pattern test.
My question is:
In normal case, we should use default value for USBPHYx_TXn, so is there any bad effect on the system if set 0x1C020003 for USBPHYx_TXn.