Full USB Host on i.MX 6SX

[DBMicro]

We are trying to provide a full USB Host connection with an i.MX 6 SoloX. My circuit for the USB interface is the following:

• NVCC_USB_H is not powered because the HSIC interface is not used
• USB_OTG2_VBUS and USB_OTG1_VBUS have their decoupling capacitors
• VDD_USB_CAP has its capacitors connected
• USB_OTG2_VBUS is not powered
• USB_OTG1_VBUS is powered by 5V
• USB_OTG1_DN and USB_OTG1_DP are connected to the USB connector (via Choke and protection)
• USB_OTG1_ID is tied to ground
• USB_OTG1_OC is connected to the overcurrent detection of the power Switch
• USB-OTG1_PWR is connected to the enable-input of the Power switch
• The power switch is shorted (5V will always be available on the connector, for testing purposes)
• USB_OTG1_CH_B is floating
• OTG2 Port is not in use

The Sabre Board provides two USB connections: one USB on the go and one USB Host (as noted on the Board's silksreen). As i reviewed the Sabre Board schematic the only differences to the "Host" USb connection are:

• We use OTG1 data ports instead of OTG2
• NVCC_USB_H is not powered in our solution

The Linux we are running does not even Probe the USB connection when connecting a USB Device (not a host). The Device seems to be powered correctly. So the question now is:

1. Is it possible to get a full USB Host without using the HSIC interface (as noted on the Sabre Board)?
2. Is the OTG1 Port capable of providing a USB Host connection or is this only possible via OTG2?
3. Does NVCC_USB_H has to be powered to use the OTG ports?

[igorpadykov]

Hi DBMicro

according to IMX6SXCEC sect.4.2.1 Power-Up Sequence :

[only] USB_OTG1_VBUS and USB_OTG2_VBUS are not part of the power

supply sequence and may be powered at any time.

so not powering NVCC_USB_H may cause problem.

Best regards

igor

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