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Roomi#0787 , 02-11-2024, 03:20 AM

I am designing a hardware based on the Coral SOM and the dev board schematic. Here is the datasheet of the SOM -
https://raw.githubusercontent.com/SeeedDocument/Bazaar_Document/master/Coral-SoM-datasheet.pdf

On page 20, there is the USB pinouts. I don't need the OTG function and want to run both the USB ports as host. There is no documentation in this respect in the datasheet.
1. For host mode, how should I configure the 4 pins, USB1_VBUS, USB2_VBUS, USB1_ID and USB2_ID ?
2. Should I connect the ID pins to GND ?
3. Whats the function of VBUS detect pins ? Does the pins state matter in the host mode ?

QDrives , 02-11-2024, 10:47 PM

OTG is selecting host/peripheral depending on the ID signal.
1+3) As for the Vbus signal it states input, but as a host you are driving it. So I do not know how this should be handled. Normally with a peripheral, the Vbus signal is an indication that the USB is connected and supplying power.
2) In most examples I see the ID pin connected to Gnd for the host.

Roomi#0787 , 02-12-2024, 01:27 AM

So, as I am using only host mode, should I leave the USB1_VBUS, USB2_VBUS unconnected ?

QDrives , 02-12-2024, 08:53 PM

I'd say you would need to go deeper into the system. The datasheet does not provide correct information about host capabilities.
As I mentioned, the host drives the Vbus, it is pointless to detect it.
Either get the schematic of SOM, find details in iMX datasheet itself or an app note.

Roomi#0787 , 02-17-2024, 01:14 AM

I think I found the problem. my board is based on the coral dev board reference design where they used PTN5150 for the OTG controller. I removed it in my design as I will only use it as host. As I loaded the BSP for coral dev board into my board, therefore the kernel sees different hardware, thats why the USB1 is not working