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SAM4L Cortex-M4 Low Power Microcontroller Slide 11
For highly integrated microcontrollers, the SAM4L offers unique low-power features. Microchip’s picoPower technology brings key low-power parameters on large microcontrollers down to levels only seen on 8-bit microcontrollers before. Taking a look at a typical low power application, CPU usage traditionally happen in bursts, with the application being in sleep modes. The system wakes up due an RTC interrupt or maybe a I2C message reception. The system then does some computation and goes back to sleep again before the process repeats itself after some time. The graph shows one iteration of this cycle. The total power consumption is the area beneath the curve. It can be seen how the impressive figures from the datasheet impact the power consumption; the fast wakeup shown on the right allows the system to be ready to start the computation faster and thus reducing the amount of power wasted to get the system ready. The lower current consumption combined with the lower voltage levels supported by the SAM4L results in that the microcontroller consumes less when in active mode. Combined with an efficient Cortex-M4 CPU, the active time for the MCU can be reduced compared to many competing solutions. High code density also makes a difference as higher density allows the user to select a smaller flash which consumes less power but it also reduces the amount of processing time needed to process the data and thus lowering the power consumption. It can also be seen that lower power consumption in sleep modes impacts the overall system power consumption too. The DMA Controller and Event System in the SAM4L allow for more data transfer and peripheral signaling to happen in parallel without using CPU resources. This can enable longer time in Idle sleep mode where the CPU is stopped, shorter time in Active mode since the CPU does not have to handle all data transfers and interrupt service routines and longer time spent in sleep modes using SleepWalking. So instead of having a power consumption equal to the area beneath the green curve, the SAM4L allows teh designer to reduce the power consumption many times fold with all the picoPower features embedded into the SAM4L.
PTM Published on: 2013-01-23