Top Considerations for Selecting a 32-bit ARM Microcontroller
Traditionally, the key factor in selecting a 32-bit microcontroller (MCU) has been the choice of central processing units. Earlier, 32-bit MCUs were based on a variety of cores , like embedded designers either had to stick with one core or significantly increase their development time to learn new hardware intricacies and port existing software code, but now days the emergence of ARM Cortex cores in MCU products has changed the embedded landscape. Developers are migrating from proprietary 32-bit cores to MCUs based on ARM Cortex processors, so they are no longer locked into a single provider for their MCUs.
Choosing the right MCU for a given application can be a difficult task with many variables to consider. First, designers must narrow the potential number of MCU choices based on a variety of "checkbox" items, such as memory size, number of input and output pins, and communication interfaces. The developers will need to refine their selection by focusing on other important factors, such as mixed-signal integration, configurability, power consumption and ease of development if they want to reduce overall system cost, design complexity and development time.
Silicon Labs' Precision32™mixed-signal MCUs are engineered to provide a number of integrated features not typically found in other MCUs, such as a USB oscillator, 5 V regulator, six programmable highdrive pins that can provide up to 300 mA of current and 16 capacitive sensing input channels for touch buttons or sliders. This high level of integration helps to eliminate the need for multiple discrete components and provides a more flexible power domain, thereby reducing the bill of materials (BOM) and simplifying the development process.
Use of highly-integrated mixed-signal MCU in Barcode scanner application
To read a barcode, the scanner shines a laser at an oscillating mirror powered by a motor. This light illuminates the barcode, and the image is then captured by a charge-coupled device (CCD) sensor. The CCD sensor is a camera that captures one line of pixels at a time, e.g., 1 x 1024 pixels. The analog light levels are shifted out and captured by an analog-to-digital converter (ADC). Having an MCU that can supply high current eliminates the need for power transistors used to drive the laser and motor. Choosing an MCU that is designed to provide an interface with the CCD sensor for clock synchronization can make a designer's job easier, as well.
Another important design consideration is the flexibility to accommodate change quickly and easily without driving up development cost. To speed development, designers often start with a previous project and modify the setting to fit the new requirements. However, to effectively repurpose the design, it is important to be able to choose and modify the MCU peripherals used and their placement. Silicon Labs dual-crossbar MCU architecture gives developers greater flexibility by enabling them to first select the peripherals needed and then choose the pin placement for them. Having the ability to "cherry-pick" only the required peripherals often enables smaller, more cost effective packaging options. Using a flexible, configurable crossbar technology, the developer could easily fit this peripheral mix into a 40-pin package with several I/Os to spare.
Some developers are concerned that a crossbar architecture may be complex to program. Silicon Labs has addressed this concern by creating AppBuilder, a free software development tool designed to simplify initialization and configuration. The GUI based AppBuilder tool enables developers to quickly and graphically choose their peripheral mix, select peripheral properties, set up clocking modes and customize pinouts, all without having to read the data sheet. AppBuilder even generates source code that can be used with popular compilers, such as Keil, IAR and GCC. A final important consideration in selecting a 32-bit MCU is power efficiency.
It is important to have a low-power sleep mode that includes a real-time clock (RTC) to wake up at a regulator internal, such as every 100 microseconds. It can be challenging to find a 32-bit MCU that excels in ultra-low power in sleep mode, active mode, wake-up time and on-the-fly frequency changes. The Precision 32 MCU family addresses this challenge by providing several low-power options and has a very low active mode of 275 µA/MHz, enabling the developer to optimize power for the task at hand.
Conclusion
Selecting the right MCU for a given design, developers can significantly reduce development time, power consumption and total system cost while gaining the flexibility to make last-minute changes without a major system redesign. In short, it makes sense to choose a 32-bit MCU with a flexible architecture engineered from the ground up to make the developer's job easier.
Choosing the right MCU for a given application can be a difficult task with many variables to consider. First, designers must narrow the potential number of MCU choices based on a variety of "checkbox" items, such as memory size, number of input and output pins, and communication interfaces. The developers will need to refine their selection by focusing on other important factors, such as mixed-signal integration, configurability, power consumption and ease of development if they want to reduce overall system cost, design complexity and development time.
Silicon Labs' Precision32™mixed-signal MCUs are engineered to provide a number of integrated features not typically found in other MCUs, such as a USB oscillator, 5 V regulator, six programmable highdrive pins that can provide up to 300 mA of current and 16 capacitive sensing input channels for touch buttons or sliders. This high level of integration helps to eliminate the need for multiple discrete components and provides a more flexible power domain, thereby reducing the bill of materials (BOM) and simplifying the development process.
Use of highly-integrated mixed-signal MCU in Barcode scanner application
To read a barcode, the scanner shines a laser at an oscillating mirror powered by a motor. This light illuminates the barcode, and the image is then captured by a charge-coupled device (CCD) sensor. The CCD sensor is a camera that captures one line of pixels at a time, e.g., 1 x 1024 pixels. The analog light levels are shifted out and captured by an analog-to-digital converter (ADC). Having an MCU that can supply high current eliminates the need for power transistors used to drive the laser and motor. Choosing an MCU that is designed to provide an interface with the CCD sensor for clock synchronization can make a designer's job easier, as well.
Another important design consideration is the flexibility to accommodate change quickly and easily without driving up development cost. To speed development, designers often start with a previous project and modify the setting to fit the new requirements. However, to effectively repurpose the design, it is important to be able to choose and modify the MCU peripherals used and their placement. Silicon Labs dual-crossbar MCU architecture gives developers greater flexibility by enabling them to first select the peripherals needed and then choose the pin placement for them. Having the ability to "cherry-pick" only the required peripherals often enables smaller, more cost effective packaging options. Using a flexible, configurable crossbar technology, the developer could easily fit this peripheral mix into a 40-pin package with several I/Os to spare.
Some developers are concerned that a crossbar architecture may be complex to program. Silicon Labs has addressed this concern by creating AppBuilder, a free software development tool designed to simplify initialization and configuration. The GUI based AppBuilder tool enables developers to quickly and graphically choose their peripheral mix, select peripheral properties, set up clocking modes and customize pinouts, all without having to read the data sheet. AppBuilder even generates source code that can be used with popular compilers, such as Keil, IAR and GCC. A final important consideration in selecting a 32-bit MCU is power efficiency.
It is important to have a low-power sleep mode that includes a real-time clock (RTC) to wake up at a regulator internal, such as every 100 microseconds. It can be challenging to find a 32-bit MCU that excels in ultra-low power in sleep mode, active mode, wake-up time and on-the-fly frequency changes. The Precision 32 MCU family addresses this challenge by providing several low-power options and has a very low active mode of 275 µA/MHz, enabling the developer to optimize power for the task at hand.
Conclusion
Selecting the right MCU for a given design, developers can significantly reduce development time, power consumption and total system cost while gaining the flexibility to make last-minute changes without a major system redesign. In short, it makes sense to choose a 32-bit MCU with a flexible architecture engineered from the ground up to make the developer's job easier.