ATmega8515 power consumption

Meindert Sprang wrote:
> "Peter" <meltyb@hotmail.com> wrote in message
> news:dsvd36$opp$1$8300dec7@news.demon.co.uk...
> > If you "enabled ALL pull-ups" then it's not isolated. Each input pin held
> at
> > 0V will source nearly 0.1mA at vcc=3.3.

Yes, you should disable pull-ups.

>
> I wrote "Yes, in fact, I disconnected ALL I/O's and enabled ALL pull-ups".
> Take that literally. I cut away all components on the board, leaving just
> the power supply and the processor. So there is nothing left to pull a pin
> down.

But it's the internal pull-ups that count. 

> 
> Meindert

"linnix" <me@linnix.info-for.us> wrote in message
news:1140021666.516170.66480@g43g2000cwa.googlegroups.com...
>
> Meindert Sprang wrote:
> > "Peter" <meltyb@hotmail.com> wrote in message
> > news:dsvd36$opp$1$8300dec7@news.demon.co.uk...
> > > If you "enabled ALL pull-ups" then it's not isolated. Each input pin
held
> > at
> > > 0V will source nearly 0.1mA at vcc=3.3.
>
> Yes, you should disable pull-ups.
>
> >
> > I wrote "Yes, in fact, I disconnected ALL I/O's and enabled ALL
pull-ups".
> > Take that literally. I cut away all components on the board, leaving
just
> > the power supply and the processor. So there is nothing left to pull a
pin
> > down.
>
> But it's the internal pull-ups that count.

Yes, but with floating pins, you have to enable the internal pull-ups, which
will not contribute to the current consumption then.

Meindert

Meindert Sprang wrote:
> I am struggling to get the power consumption of sensor device down.
> According to the datasheet (page 208, top graph), the ATmega8515 I use, uses
> slightly less than 1mA @ 3.3V and 1MHz internal clock while active. But I
> measure around 2.3mA. Even when I stop all I/O and go into an endless loop,
> it still uses 2.1mA. Is Atmel showing off here or am I missing something?

  Try an external SqWave Clock of 1Mhz, and see if that matches the 
External Clock curves.
  That will tell you if the core is higher, if the RC osc is higher.
  Try more than one device.
  These curves are 'typical' , not maximums :)

-jg

comparator?

Hul

Meindert Sprang <ms@nojunkcustomorspamware.nl> wrote:
> "larwe" <zwsdotcom@gmail.com> wrote in message
> news:1140011985.291845.151910@g14g2000cwa.googlegroups.com...
> >
> > Meindert Sprang wrote:
> >
> > > Yes, in fact, I disconnected ALL I/O's and enabled ALL pull-ups. So the
> only
> > > active circuits where the VCC and GND connected to the power supply and
> one
> > > pull-up resistor to the RST input. I'd call this a completely isolated
> AVR.
> >
> > Any timers running? Worthwhile going down the peripherals list and
> > making sure everything is switched off.

> No timers, just one external interrupt, but I tested with interrupts
> disabled.

> > Brownout detection enabled? Try turning it off.

> Makes no difference.

> Meindert

"Hul Tytus" <ht@panix.com> wrote in message
news:dt0eub$6eb$1@reader2.panix.com...
> comparator?

Not used.

Meindert

"Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> schreef in bericht
news:11v88b896d7e0f4@corp.supernews.com...
> "Hul Tytus" <ht@panix.com> wrote in message
> news:dt0eub$6eb$1@reader2.panix.com...
> > comparator?
>
> Not used.

Silly question perhaps, did you check the meter ?

-- 
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)

"Frank Bemelman" <f.bemelmanq@xs4all.invalid.nl> schreef in bericht
news:43f44074$0$8268$e4fe514c@dreader30.news.xs4all.nl...
> "Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> schreef in bericht
> news:11v88b896d7e0f4@corp.supernews.com...
> > "Hul Tytus" <ht@panix.com> wrote in message
> > news:dt0eub$6eb$1@reader2.panix.com...
> > > comparator?
> >
> > Not used.
>
> Silly question perhaps, did you check the meter ?

Another silly idea... feed the chip through a 100 ohm resistor, and
put a nice cap between VCC and GND. Measure the voltage over the resistor.
Perhaps your meter gets upset by noise or something other strange phenomena.

-- 
Thanks, Frank.
(remove 'q' and '.invalid' when replying by email)