Re: [Gumstix-users] robostix ADC at 2.1v not 5v ??

[Dave H. <dhy...@gm...>]

Hi Andrew,

> Yesterday my wifistix/verdex/robostix stack was working fine to perform an
> altitude hold on a heli by reading an ultrasonic ADC sensor for range and
> manipulating rotorspeed through the PWM port.
>
> I wake up today and turn it on and am getting a zero voltage reading through
> the ADC pin, when i checked the voltage across all 7 of them, they are all
> 2.1v, the rest of the pins on the board are still reading 5V. I am not sure
> what is going on since I haven't changed anything since yesterday??
>
> The other thing is, prior to my last filesystem and kernal flash, i had
> loaded dave'si2c-boot.....hex and i2c-io.hex into the robostix, now,
> everytime i reboot the gumstix, these are removed form the robostix flash
> for some reason and i have to reload them each time i reboot using uisp.
> thoughts?

That sounds really weird. It's like the AVCC voltage regulator isn't
running properly.
See:
<http://docswiki.gumstix.com/Robostix_troubleshooting>

If the AVCC isn't turned on, you'll get leakage voltage from the other
supply which can cause the low voltages you're seeing.

I don't understand why you would need to reprogram the flash. I'm more
likely to suspect fuse settings being incorrect.
You can try reading the flash to see what it contains. If it runs
anything, it's running from flash, which is nonvolatile.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/