HOWTO: Enable USB device mode on Pi Zero

[MattDwnr]

If you use the modular kernels, you can flip between device and host mode easily:

http://pi.gbaman.info/?p=699

just playing with that now.

I'm having trouble getting this set up, I can't get any further than step 4/5?

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pi@raspberrypi:~ $ sudo echo "dwc2" | tee /etc/modules
tee: /etc/modules: Permission denied
dwc2

[mattmiller]

I got this and thought it was just me
Just sudo nano the files instead

Matthew

[rpdom]

Just sudo nano the files instead

Probably the best option.

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pi@raspberrypi:~ $ sudo echo "dwc2" | tee /etc/modules
tee: /etc/modules: Permission denied
dwc2

Not the best way to do it, even if it did work. The "tee" in this case would (if allowed) overwrite the contents of /etc/modules. It isn't allowed because the sudo is in the wrong place. What you should do (if you want to do it this way) is

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pi@raspberrypi:~ $ echo "dwc2" |sudo tee -a /etc/modules

That will add "dwc2" to the end of /etc/modules

[DirkS]

That will add "dwc2" to the end of /etc/modules

I had a play with it the other day and AFAICT you actually don't need that entry in /etc/modules.

[findx]

Has anyone done a speed benchmark for the virtual Ethernet adapter? I'm curious how much data it can push, but I unfortunately do not have an RPi Zero to test it.

[mattmiller]

Its much faster than WiFi - basically you've got a 480Mbs dedicated network

[notro]

That will add "dwc2" to the end of /etc/modules

I had a play with it the other day and AFAICT you actually don't need that entry in /etc/modules.

You're right, dwc2 is automatically loaded by udev, but this happens after /etc/modules is processed so if a gadget module is loaded in /etc/modules, dwc2 must be loaded there to.
More: https://github.com/raspberrypi/linux/pu ... -170253586

BTW I've looked at how we can get a usb console in default Raspian by just editing config.txt: https://github.com/RPi-Distro/repo/issues/17

[mattmiller]

Just done a test
Over Wifi - 7 mins 30 secs to transfer 400MB file
Over USB 2mins


Matthew

[DirkS]

That will add "dwc2" to the end of /etc/modules

I had a play with it the other day and AFAICT you actually don't need that entry in /etc/modules.

You're right, dwc2 is automatically loaded by udev, but this happens after /etc/modules is processed so if a gadget module is loaded in /etc/modules, dwc2 must be loaded there to.
More: https://github.com/raspberrypi/linux/pu ... -170253586

Ah, yes. It worked for me then because I used modprobe to load the gadget modules.

[findx]

@mattmiller Thanks for running a test!

[notro]

I've made a systemd service that loads g_ether with static mac addresses: https://github.com/RPi-Distro/repo/issu ... -175140984

[AndyPi]

I must be doing something wrong! Got my Pi zero and want to experiment with the usb device mode. I am having trouble with the simple use of rpiboot.

I have compiled and installed the rpiboot program on Ubuntu 14.10 PC. Got a pi zero with empty sd slot, usb micro to USB A cable connected to USB slot.

Plug in Pi0 to USB port on Ubuntu PC and get the

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lsusb
Bus 002 Device 005: ID 0a5c:2763 Broadcom Corp. 

So far so good.

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sudo rpiboot -v
Waiting for BCM2835 ...
Found serial = 0: writing file /usr/share/rpiboot/usbbootcode.bin
libusb_bulk_transfer returned 0
Writing 16674 bytes
libusb_bulk_transfer returned 0
Successful
Waiting for BCM2835 ...

and it just waits...

Looking at the rpiboot code (main.c) it seems that it enumerates with serial=0, successfuly sends the usbbootcode.bin, and reads the response which is OK ie 0.

It then waits for the Pi0 to enumerate serial = 1 before it progresses to stage 2. Mine seems not to re-enumerate.

The lsusb listing disappears after the read response.

Looking at posts here and there it seems that most people are not having problems with this and the pi0 re-enumerates quickly.

I've tried same procedure but with PiB2 (ARCH 4.1.17) as host with same result. I've even used USB port on powered hub to exclude (as far as I can) power issues.

I must be doing something stupid since it appears to be working elsewhere and recently too.

can anyone help?

regards

Andy

[gregeric]

I've experienced similar issues. Seem to be solved by using shorter, higher quality cabling. I've a 150mm long micro USB cable which came with some old Nokia phone, that works well.

[AndyPi]

I have a couple of cables with male micro A / male USB-A. Not sure where they came from, do I need something extra special. As I said the Pi0 seems to enumerate when connected using this cable and am able to send usbbootcode.bin OK and read response, just doesn't want to re-enumerate after the bootcode runs.

Ill try another cable...

[AndyPi]

Tried three cables. A short one (250mm) from Chromecast kit (I think), one from TomTom kit, one from newish Motorola smart phone. All give same results.

[gregeric]

My current working set-up for this is RPi2B with WD PiDrive kit, short Nokia micro-USB cable to Pi0.

It won't do any harm to add a second micro-USB to the Zero's power in port (so long as it's fed from the same hub or port on host Pi), see if that improves it.

[AndyPi]

Connect to my PiB2, Logik 2A 4 port hub, with power and usb ports

dmesg

• usb 1-1.4.1: new full-speed USB device number 12 using dwc_otg
  usb 1-1.4.1: New USB device found, idVendor=0a5c, idProduct=2763
  usb 1-1.4.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
  usb 1-1.4.1: Product: BCM2708 Boot
  usb 1-1.4.1: Manufacturer: Broadcom

rpiboot -v

• Waiting for BCM2835 ...
  Found serial = 0: writing file /usr/share/rpiboot/usbbootcode.bin
  libusb_bulk_transfer returned 0
  Writing 16674 bytes
  libusb_bulk_transfer returned 0
  Successful
  Waiting for BCM2835 ...

dmesg

• usb 1-1.4.1: USB disconnect, device number 12

[Killertechno]

2. Modify the bcm2708_common.dtsi file.
You can do this either my applying this patch or by editing arch/arm/boot/dts/bcm2708_common.dtsi and changing the section that reads:

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                usb: usb@7e980000 {
                        compatible = "brcm,bcm2708-usb";
                        reg = <0x7e980000 0x10000>,
                              <0x7e006000 0x1000>;
                        interrupts = <2 0>,
                                     <1 9>;

to read:

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                        compatible = "brcm,bcm2835-usb";
                        reg = <0x7e980000 0x10000>;
                        interrupts = <1 9>;
                        g-np-tx-fifo-size = <32>;
                        g-rx-fifo-size = <256>;
                        g-tx-fifo-size = <256 128 128 64 64 64 32>;

Sorry guys, I'm noob in Kernel.....
So you mean I must select (changing dtsi) if USB port can work as gadget or host (for keyboard or mouse)?
But about other Raspberry versions, how can I set some USB ports for gadget and remaining for keyboard and mouse?
I'm trying to cross-compile Raspberry kernel on Ubuntu: I set gadget mode through "make menuconfig", after boot I can see USB0 port through ifconfig, but nothing happening when I plug USB cable.......
So it's the device-tree to be changed?
Thanks.
Thanks.

[hirenvador]

Hello,
I am trying to enable USB device as Mass storage mode.I am having trouble in that.
My device is detected as unknown USB device(Device description not found).

Any help will be appreciated.

Thanks in advance.
Hiren