IMX8MM Minimum USB Configuration for Download

[user1092]

Hello,

I would like to implement the minimum circuitry for USB to be able to download/flash via UUU. This is the only purpose of the USB port in this design.

I have seen the following post: https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX8MM-i-MX8MQ-USB2-0-Design-Without-US...

This post uses the USB1_OTG_ID (GPIO1_IO10) pin to configure the IMX8MM as a host or peripheral.

I have no interest in operating the USB as a host. Is it still required to pull-up USB1_OTG_ID (GPIO1_IO10) to +1V8?

If this is possible, are there any device tree changes requried once the system is up and running? Ideally there is no reason for USB to be operating once in the Linux environment.

Thanks,

Chris.

[Rita_Wang]

It depends on your design. How about the usb interface are you using Type-C or micro USB?

[user1092]

Appologies forgot to include, the intention is for a micro usb connector.

[Rita_Wang]

OK, if you use the micro usb and connect the usb1_otg_id, you need to pull it to (GPIO1_IO10) to +1V8.

[Adele]

@Rita_Wang 

I'd like to know what the purpose of the USB ID(legacy) or DRD is when USB is only used as a device/peripheral. In other words, the ROM code only defines the device. The UUU's function is simply to communicate with the USB device. How does this relate to the type of USB connector, especially if it's only used as a USB device?

[Rita_Wang]

You just need change the dr_mode to the  "peripheral":

&usb_otg1 {

    dr_mode = "peripheral";  /* Options: "host", "peripheral", "otg" */

    status = "okay";