USB Switch - Host or Device


#1

USB Switch - Host or Device.

What is the difference, I have tried Google but its all a bit fluffy.


#2

I understand it that way:

USB Switch - Device : Several devices are connected in parallel and the software selects the desired device.
USB Switch - Host : One device is connected to several hosts via the switch and can be assigned to one host alternately. This is also available as LAN version with virtual USB over Ethernet driver.


#3

Host is for connecting other peripheral such as usb drive, usb printer, usb camera etc…

Device is ROCK Pi 4 as a peripheral connecting to other PC, such as you can export the eMMC/sdcard to be read by the PC as MTP device.


#4

Jack,

Thank you that’s clear now.

Useful too !!!

Little off topic but any plans for you (RADXA) to release a sealed case we can use when the lareg heat sink is fitted ? … Large Heatsink with Case


#5

Wait, what?! That’s great option!


#6

well, this is the default behaviour on android as MTP device.


#7

Jack,

“Device is ROCK Pi 4 as a peripheral connecting to other PC, such as you can export the eMMC/sdcard to be read by the PC as MTP device.”

This works … thats great but balenaEtcher wont see this a drive … can SD cards be flashed via windows and balenaEtcher this way ???


#8

In theory, it’s possible. There is a command in the u-boot, which can export the emmc/sd card to host PC. Then, you can use dd or etcher.

To export eMMC to host PC, you can input the following command in u-boot serial console.

ums 0 mmc 0

I haven’t actually tried dd the whole image, but we use it to replace/update kernel/dtb in debugging.


#9

“u-boot” … assume this is edited on the Pi itself … can i do this via the android Distro ???


#10

ok, I know what you want. What you want, is actually install images from the USB OTG port, right? Here is the solution for you:

https://wiki.radxa.com/Rockpi4/dev/usb-install

You can write from PC with rkdeveloptool. Make sure you are writing the image ends with -gpt.img.


#11

From your link I went onto https://wiki.radxa.com/Rock/flash_the_image

This worked well until i tried to Flash the firmware and got “match device type failed”