"Nano" mega328P low-power bootloader

I´ve spent hours trying to get a "power down" below 70µA with the "Nano". (I put a switch on the CH340G (china replacement of the FT232 chip, or whatever it is called, so I can remove the supplies to that chip). All arduino pins drive to zero, to they are stable and won't backfeed the CH340G and I follow the examples regarding the powerdown pre-procedure, using "power.h". That's just the background. Here's the question:

I read that the normal bootloader won't make you approach the 1µA, which one would expect if it was a non-bootloader application. There is "optiboot" available which seem to do a better job regarding the power consumption. Have any of you have some experience of replacing the bootloader? Or is it a work around to keep it? I mean will the bootloader override or deny any register poking I try to make?

beavisbutthead: I read that the normal bootloader won't make you approach the 1µA

This is not true. The bootloader only runs once after the AVR restarts. After that your sketch has complete control over the chip including power down modes etc. I recommend this for a start, but I think your problem is hardware-related, something other than the AVR is drawing power

Did you turn off the ADC? If not, it wastes power while in sleep, and that amount of wasted power sounds about right. See the bit about ADC noise reduction mode in the datasheet - that's a mode where they sleep the chip during the ADC conversion. That's where they mention this issue,

Try unsetting the high bit (ADEN, ADC Enable) of ADCSRA before sleep:

ADCSRA &=127

then when you wake up turn it back on.

ADCSRA |= 128

Throw away the first ADC reading after you turn it back on.

@olf2012: That's good. This guy posting the thread (http://forum.arduino.cc/index.php?topic=78430.0) had the same problem as I have. But I don't know which bootloader to replace with, or why that helps, if your statement is true that the bootloader only runs at restart.

All pins ont the CH304G reads 0V when I have the switch off. I even removed the tantalum capacitors and LED resistors just in case. The Vin regulator is also removed.

@DrAzzy: I set the entire register ADCSRA to 0.

This guy has the similar problem. He had to modify the fuse bits. Can I connect a programmera and do that without jeopardizing the bootloader function?


I also removed the CH340G completely, but the current stayed the same. So now the :328 consumes the current all alone.

Solved: I had to disable BOD exactly before enter sleep.