Embedded developers creating low-power, sensor-based applications need to keep a variety of design requirements in mind in order to make their product viable and competitive in today’s market. Some of the most important criteria are as follows:
Our 8-bit PIC® and AVR® MCUs come with a robust set of Core Independent Peripherals (CIPs) that can help you meet those needs while getting you to market before the competition. Here are a few we’d like to highlight:
Analog-to-Digital Converters (ADCs) with Enhanced Features
When designing applications that revolve around sensing real world data the efficacy of your ADC can be the deciding factor for the success of a design. The ADCs that come embedded in our microcontrollers are equipped with a whole host of features that can help dampen noise, lower overall power consumption and reduce code size.They can operate while the CPU is in a low power sleep mode, only waking once a conversion has been completed and the result is ready to be read. This mitigates noise by turning off various clocks and other digital processes that can distort the original signal. Our newer ADCs feature context switching and channel sequencing. Context switching enables a single ADC to sample from four different analog inputs while channel sequencing allows you to automatically switch context without the need for any intervention from the CPU. Many of our ADCs can accumulate/average samples to reduce the effect of random noise which can then be compounded with the customizable low pass filter found within the ADC to further reduce noise. All these functions are handled within hardware, saving you valuable memory space and, by extension, reducing the amount of power your application will require. These are just a few of the features you can use to improve any power conscious sensor-based design.
Analog Peripheral Manager (APM) and Peripheral Module Disable (PMD)
The Analog Peripheral Manager and the Peripheral Module Disable are two features that revolve around reducing power consumption. The APM is a dedicated on-chip timer that allows you to easily toggle power to analog peripherals so that you are only activating them when you need to. The PMD’s approach to power conservation involves stopping all clock sources to the chosen peripheral, limiting current leakage. These peripherals, among others, allow you to design with confidence that you have all the tools needed to optimize power consumption.
On-chip Internal Signal Routing and Multi-Voltage I/O (MVIO)
Designs that require multiple sensors run the risk of being slowed down by costly software routines and perpetual CPU intervention. Our microcontrollers come with a variety of peripherals that can prevent that by offloading much of the triggering and routing that would normally be CPU dependent onto on-chip hardware. CIPs like the Configurable Logic Cell (CLC) on PICs and the Configurable Custom Logic (CCL) on AVRs can be used to create complex logic trees which automate task handling. The Event System (EVSYS) and other similar peripherals enable you to set up connections between CIPs, reducing the number of pins required and saving application space. In the situation where you have sensors operating at different voltage domains our Multi-Voltage I/O allows you to seamlessly integrate them both into your design without the need for external hardware. Our Multi-Voltage I/O's have a recommended voltage range of 1.8v-5.5v. The sensors that are operating at a higher voltage are less susceptible to noise, making your application more robust. These features allow the CPU to handle other tasks or enter a power saving sleep mode without losing any functionality.
Cyclical Redundancy Check (CRC) Clock Failure Detect (CFD) and Windowed Watchdog Timer (WWDT)
Low-power sensor designs are often needed to withstand harsh environments for prolonged periods of time, this is why it is critical to their continued operation to have the ability to determine if something has gone wrong and to course correct when necessary. Our MCUs have the ability to do this with the help of a few key CIPs. The Cyclical Redundancy Check is a commonly used error checking technique that verifies the integrity of data by taking an initial checksum and comparing it to a freshly generated one later. If there is any difference, the CRC will know the data has been corrupted. The Clock Failure Detect constantly monitors the main clock of the MCU and, should that stop, will automatically swap over to a different clock to maintain normal operation with minimal pause. Similarly, the Windowed Watchdog Timer monitors the amount of time taken to execute software and issues a reset to the MCU should it fall outside normal operating levels. We also have features such as the High-Low Voltage Detect (HLVD) which can help monitor voltage levels for batteries, further ensuring reliable operation over long periods of time. All of these features and more come standard with most of our MCUs in order to ensure that your application is able to hold up against whatever you throw at it.
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