Rock 5B USB OTG

#1

Hi,

I would like to buy a Rock 5B, being mainly interested in using it as a USB gadget. I know that the 4B has a USB 3.0 OTG port which is meaningful if the 4B is used as a USB mass storage gadget. I try to find out if either the 5B (3588) or 5A (3588S) has a USB 2.0 or 3.0 OTG. I can’t find this info in the wiki. When I search on the web, some sites indicate 3.0 OTG but the specsheet of the 3588 chipset shows that its OTG function is tied to a 2.0 port. Can you please clarify this point for me before I make a purchase?

Thanks

Michael

#2

5B has it, but it is disabled by default. You can enable it in sysfs(need to look up the exact path myself)

Edit: I only tested this on the c-type port

#3

Thanks John. So you are saying the 5B can do OTG in both its USB 2.0 and 3.0 ports, at their respective speeds?

Michael

#4

I have tried USB OTG on Type-A ports but no luck. Seems there is not a single successful try since rock5 launched.

#5

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图片.png926×189 20.4 KB

(from radxa_rock_5b_v1423_sch.pdf)
The VBUSDET pin is floating, that seems to be violating the design guide and could be a possible cause to the Type-A device mode malfunction.

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图片.png835×438 64.8 KB

(from gitlab.com/rk3588_linux/linux/bsp/docs/-/blob/master/Common/USB/Rockchip_RK3588_Developer_Guide_USB_CN.pdf)

#6

Thanks hallo1. This seems quite confusing. The type C port is USB 2.0 or 3.0???

#7

3.0 with support for alternative mode and otg

#8

Does anybody know why you only get OTG via USB2.0 and not USB3.x. That is, the connector my be Type-C, but the speed is always maximum 480Mbps and not 5Gbps? Is this a Linux gadget restriction?