Microcontrollers Lab 10

Lab 10: Power Consumption & ATmega328P without Arduino

Lab 10 will come from the published version of the lab manual.

Lab Manual Errata

The following are known errors in the lab manual corresponding to this lab.

  • Page 114 should say “Using your optimized code from circuit II, …”
  • Page 111: the frequency/Vcc graph is for the ATmega328, not for the ATmega328P. See below for the figure for the ATmega328P.
  • Circuits II and III: do not use a Vcc less than 2.7 V (which is the minimum allowable Vcc value of the ATmega328P chip.)
Relationship between Vcc and clock frequency for the ATmega328P microcontroller.

Clarification

Here are some details to make the circuits more clear.

  • Dr. P needs to see that your LED is visibly ON in all three circuits.
  • Vcc must be the same for both LED ON and LED OFF scenarios. (Don’t use a smaller Vcc with the LED off. Assume you are writing code for a circuit where you cannot just change Vcc all the time.)
  • Circuit 1 must have a Vcc of 5 V for both LED on and LED off. This is a baseline, you want to know where you started from.
  • Circuit 2 and 3 can have a Vcc down to 2.7 V, but only if the LED is visibly ON. (In circuit 2, the LED must be visibly ON with the USB cable disconnected from the Arduino Uno.)

Lab Modifications

The following changes have been made to lab 10.

  • In the procedures and results section for each circuit: Based on the feedback you’ve received on your code, and anything new you’ve learned since the lab, what, if any, changes would you make to your code?

Dr. P’s Best Power Values

In May 2022, here are the values Dr. P got without spending a ton of time optimizing. (You can do better!)

CircuitLED ONLED OFF
1213 mW166 mW
2125.4 mW98.6 mW
32.6 mW2.3 mW

Resources

Watch/read the following resources prior to attending this lab. This information will teach you how to use lab equipment and provide suggestions and technical tips for successfully completing the lab.