RE: [Gumstix-users] Audiostix II -R781

[David V. <dve...@ta...>]

Pascal is correct. The designs I have seen use the A/D channels on the
UCB1400 for things
like battery management, supply monitoring etc. The digital IO is usually
used for things like turning the backlight of an LCD display on/off and
enabling/disabling voltage regulators for various peripherals etc.

DV
  

-----Original Message-----
From: gum...@li...
[mailto:gum...@li...] On Behalf Of Pascal A.
Brisset
Sent: Saturday, March 25, 2006 9:14 PM
To: gum...@li...
Subject: Re: [Gumstix-users] Audiostix II -R781

Gordon Kruberg writes:
 > - Similarly, how about an optional jumper between V_BATT and AD0 ?  (The
> UCB400 has internal resistive voltage dividers on ADx.)  > Not done,
subject to my understanding a bit more about the goal.  
 > Question I have is whether this was really for V_Batt (vs. AVdd or Vcc)

Definitely V_BATT.

Section 11 of the UCB1400 datasheet says "... This makes these analog inputs
very suitable to monitor battery voltages."
Section 15 says the input range is 7.5 V.

Disclaimer: I haven't actually tried it. But it looks like these inputs are
really intended for battery monitoring. The idea would be to allow a system
to do something before the CPU is undervolted or before LiPo batteries get
overdischarged.

-- Pascal