Doesn't it do that in normal mode anyway? When you plug in the usb cable to the PC you can't access the MMC card from apps on the 770.

Time to start the Wiki entry?

That's correct - but when you're accessing the rs-mmc card over usb using your desktop, it's both useful and necessary to unmount it. In host mode, there's no reason to unmount, so I want to stop that behaviour.

I spent a little time playing with the "software" based host vs peripheral mode toggles, which, BTW are:

command to put it into host mode:
echo host > /sys/devices/platform/tahvo-usb/otg_mode

command to put it into peripheral mode:
echo peripheral > /sys/devices/platform/tahvo-usb/otg_mode


First, you need to log in as root to execute these commands.

Next, there are some quirks:

If in flashed host mode (ie "./flasher --enable-usb-host-mode"), this method doesn't work. You can change the otg_mode file to "peripheral", but it's still host, and every time you reboot, otg_mode is changed back to 'host". Also, in flashed USB host mode, the mmc does not unmount if you plug the USB cable into a PC.

If in flashed peripheral mode (ie the vanilla state), the software toggle works as reported, but when otg_mode contents are changed to 'host", the mmc will unmount if USB cable is attached to a PC (but not a peripheral).

Personally, I can live with the flashed peripheral mode quirks. It's really nice to be able to switch modes in software.

John

Joh Bigboote, great name by the way! Wonderful film. You try to explain it to people and they think you're mad

I built my little USB host box tonight. Way over engineered and complicated but fun to make. I'll put some pics up on my site soon. I don't have my USB keyboard yet to test it (and I need to charge the batteries). Can someone please explain the mounting a USB device that Bhima mentioned earlier. I am a Linux newbie so I only have a vague understanding of how that works and how I use it. I basically got as far as enabling host mode via x terminal with root access. When I plugged in my little box it would detect the USB cable was connected but then I didn't try anything with it since the batteries were uncharged. I do have a USB thumb drive and a USB card reader. How can I use them to test if everything is working?

Thanks!

Simon

OK. I put some pics of my little powered USB box up at http://www.asciimation.co.nz/770

The page is really crappy but hey, it's 1 am here and I should be asleep!

I haven't tested it fully yet since I am am waiting for the batteries to be fully charged first.

I can't really provide full instructions since 1, I made it up as I went along and 2, it doesn't need to be this complicated. I just like an excuse to waste time making gadgets!

Simon:

Congratulations! Yours is now the itT post that makes me the most jealous!!

D/L your EE skillzz into my head so I can make one of those too!

Bloody excellent work there!

It's BigbooTE, TE! Monkeyboy!

I agree with Mike, that's some seriously pro looking EE hacking there. Kudos.


For mounting a USB thumbdrive (or card reader), see:
http://www.internettablettalk.com/fo...mount#post4298

A while back, I posted instructions for how to modify a mini-hub to send power back to the 770. For a portable rig, this would require a regulated power supply.
http://www.internettablettalk.com/fo...akoss#post4113

John

Ah thanks. I must have missed those links. We need to be more organised. It's easy to lose stuff in the forums.

I think I overcompensated on my EE gadget building to make up for my complete lack of Linux skills! Batteries should be charged now. It didn't burn my house down overnight (or even get warm) so tonight after work I will try mounting my USB drive or card reader and see how that works.

Damn. You win the internet. I lose.