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Topic: ATMEGA328 Power Options (Read 267 times) previous topic - next topic

goatherder

Hello!

I have an Arduino Nano-based project that reads voltages at analog pins A0-A4, saves those values to a microSD card via a microSD driver, and occasionally writes to a buzzer depending on the values read. I've been powering the device with a 7.4V 2s Lipo battery. I would really like to use a 3.7 V battery, there are a lot more size/shape options available at a lower price than the 2s ones.

I've seen online that the ATMEGA328P that the Nano uses requires >=5V to allow the 16MHz clock speed without overclocking, and that the analog pin readings could get glitchy if I try and power with something below 5V. But I also know Arduino has boards that use the ATMEGA328P and run below 5V, like the Feather. Does the 328P require more than 5V or not?

Also, I'd like to move to my own PCB for the next prototype. Should I stick with the ATMEGA328P, or is there another microcontroller that would give me better resolution/power usage/accuracy ?

WattsThat

If you want to run at 3.3 volts, the clock needs to be reduced to 8MHz. Consult the atMega328 datasheet for the allowable range of clock speed versus supply voltage.
Vacuum tube guy in a solid state world

vaj4088

The 328P can use a lower voltage (say, 3.3 volts) at a lower frequency (say, 8 MHz).  The lower frequency should not be an issue for a datalogger.

If you do this yourself, watch out for timers and baud rates and other time-related things.


jremington

#3
Jul 05, 2020, 12:52 am Last Edit: Jul 05, 2020, 12:55 am by jremington
For lowest power operation, use a 3.3V Pro Mini, which you can interface directly to an SD card. You were misinformed about the ADC, it works perfectly well at 3.3V and lower.

The Nano is a poor choice because of the extra circuitry on the PCB.

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