Squeeze Power from Your MCU Using the IDE
An IDE that offers integrated current measurement can help developers take advantage of advanced MCU features that can dramatically affect processing performance.
Today is the golden age of low-power microcontrollers. There are a half-dozen vendors offering advanced features in their MCUs that can help you to save power in your next microcontroller designs. However wading through all of these features can be daunting. To make matters worse, the pay-off is often unknown. Which features are big impact and low effort? Which features are all effort and no impact? Perhaps the most pressing question is: What is the effect on my performance? Many features in today’s MCUs dramatically affect the processing performance.
One way to address these concerns is to choose an integrated development environment (IDE) that offers integrated current measurement. How does this help? It takes the guesswork out of introducing low-power features into your code base. In the past, the trusty ammeter was the tool of choice, but the ammeter does not link current consumption to code execution in real time.
By choosing an IDE that features integrated current measurement, you can get immediate feedback on how a feature is affecting both power and performance. This allows you to instantly gauge the tradeoff being made.
Let’s look at an example case with a typical microcontroller. This microcontroller features a power mode called Idle. In Idle mode, the CPU is stopped but the peripherals continue to run. The CPU wakes upon interrupt, and this represents a tradeoff between power and performance. In normal Run mode, the current consumption is 150 µA/MHz, but by using Idle mode, the current consumption is cut by 73% to just 43 µA/MHz. Let’s say you decide to use the Idle feature whenever you transfer data over a universal asynchronous receiver/transmitter (UART). An IDE with real-time power measurement would allow you to see the incremental current savings, and the negligible performance impact that results from sitting in a while loop and waiting for the UART to finish transmitting. The impact on power and application performance can be measured directly, rather than indirectly with an ammeter.
With integrated measurement, you can now be deliberate in your approach to power savings. Starting with a power budget, you can construct scenarios that adopt low-power modes. Then, using an IDE with power measurement, you can test these scenarios and validate the savings. In addition, the tools will help you understand the effects of coding style on your application by giving real-time feedback.
The golden age of low power is upon you, but you have to use the right tools. Budgeting gets you started, but having integrated measurement takes the guess work out of implementing low-power features in your design. You can achieve dramatic improvements by incorporating the advanced features on today’s MCUs, but the impact on performance must be managed. That task is made easier and can be done in real time with an IDE featuring integrated current measurement.
Jason Tollefson is senior product marketing manager for Microchip Technology’s MCU16 Division, specializing in low-power microcontroller products. His responsibilities include new-product definition and low-power marketing for Microchip’s PIC24 and dsPIC® microcontroller product lines. Jason holds a bachelor’s degree in electrical engineering from the University of Minnesota’s Institute of Technology, and a MBA from the University of Phoenix. Jason worked in new-product development, including design/test/product engineering, for 8 years before moving to marketing.