Introduction to Microcontrollers Lab Manual - Microchip

9.3 THE LAB
9.2.7 Microchip XLP Technology
As more electronic applications require low power or battery power, energy conservation
becomes paramount. Today’s applications must consume little power and, in
extreme cases, last for up to 15-20 years, while running from a single battery. To enable
applications like these, products with Microchip’s nanoWatt XLP Technology offer the
industry's lowest currents for Run and Sleep, where extreme low-power applications
spend 90%-99% of their time.
Benefits of nanoWatt XLP Technology:
• Sleep currents below 20 nA
• Brown-out Reset down to 45 nA
• Watchdog Timer down to 220 nA
• Real-time Clock/Calendar down to 470 nA
• Run currents down to 50 µA/MHz
• Full analog and self-write capability down to 1.8
Visit www.microchip.com/xlp for more information.
9.3.1 Objective
Using the Lab 2 framework, use the power reduction concepts of the pre-lab to reduce
the total power consumption of the system. Measure the power consumed to confirm
that the changes are effective in reducing power.
9.3.2 Pertinent Information
The clock setup is configured in both configuration bits (set during programming and
specified in file config_bits_pic24fj256gb110.inc) and control register bits
(dynamically set by the application code at run time).
If the main clock frequency is changed, then the timer pre-scaler settings may need to
change.
Use a voltmeter to measure the voltage across the input power measurement resistor
(R32). This is a 0.1 Ohm resistor, and by using the equation P = VI, the total current
consumed can be calculated. Do this for the project before and after the power consumption
changes are made and record your results.
2011 Microchip Technology Inc. DS51963A-page 67