ATMEGA Chip consuming more current than the datasheet states

Hi,

I have set up my ATMEGA328P-PU on a breadboard and am runing off a bench power supply at 5V with just a 16Mhz crystal and a 10K pull up on pin 1 (to prevent reset). I have a precision multimeter wired up in series between the bench power supply and Vcc of my breadboard. After checking the data sheet for the current consumption:

http://www.atmel.com/Images/doc8161.pdf
Page 399,

I would expect about 9mA. Agree? However am I reading about 18 mA. In all the power modes, I am finding that I am consuming more current than the graphs show I should. Any idea why this is so?

Thanks
Kiwi

Look at the first page of chapter 29, those currents are with all peripherals disabled.

All Active- and Idle current consumption measurements are done with all bits in the PRR register
set and thus, the corresponding I/O modules are turned off. Also the Analog Comparator is disabled
during these measurements. The ”ATmega88PA: Supply Current of IO Modules” on page
356 and page 380 shows the additional current consumption compared to ICC Active and ICC Idle
for every I/O module controlled by the Power Reduction Register. See ”Power Reduction Register”
on page 42 for details.

More good tips here too.

AtmelAVR4013 picoPower.pdf (92.4 KB)

i tried running with power_all_disable() and the current is still higher than what it should be.

Is that what I should of used?

Thanks
Kiwi

Kiwibird:
i tried running with power_all_disable() and the current is still higher than what it should be.

Is that what I should of used?

I don't think that's enough. Read this thread about the very subject:
http://forum.arduino.cc/index.php?topic=53821.0