Only Use USB OTG 1 for serial download

[harsh_mistry]

Hi experts,

In our custom board design with i.MX8DualXPlus / i.MX8QuadXPlus,

we require one USB 2.0 OTG port with USB micro-AB port for the serial download mode to flash image by MFG tool via USB interface.

We have decided to use USB OTG 1 for this purpose.

We do not require the USB 2.0 or USB 3.0 functionality of USB OTG 2.

We have the following concerns:

1. Will it be able to detect the USB device in MFG tool if we use USB OTG1?

2. Can we leave USB OTG 2 connections (the SS pairs, REXT, OTG2 DP/DM/ID) unconnected?

3. If not in 2.; do we have to connect them as shown here in the image?

    The connections are done as per recommended in the Hardware Design Guide document "IMX8MEKHDG"

4. Is the overall circuit in the image OK?

5. What are the necessary changes to be done in the firmware to support this?

Regards,

Harsh

[igorpadykov]

Hi Harsh

>1. Will it be able to detect the USB device in MFG tool if we use USB OTG1?

yes,  in serial download mode which uses uuu tool, both OTG ports are polled until activity is
detected on one of the ports.

>2. Can we leave USB OTG 2 connections (the SS pairs, REXT, OTG2 DP/DM/ID) unconnected?

no, recommended to follow sect.7.15.2 i.MX8 QXP unused input/output guidance

i.MX 8QuadMax/i.MX 8QuadXPlus Hardware Developer’s Guide

3. If not in 2.; do we have to connect them as shown here in the image?

right.

Best regards
igor
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