As a self-contained system containing a CPU, memory, and peripherals, a microcontroller can be utilized as an embedded system. Most microcontrollers in use today are integrated into other pieces of equipment, including computers, smart phones, gadgets, cars, and other technology. While some embedded systems are highly advanced, many have modest memory and programme length requirements, no operating system, and simple software. Typical input and output devices include switches, relays, solenoids, LEDs, tiny or specialized liquid-crystal displays, radio frequency devices, and sensors for data like temperature, humidity, light level, etc. Embedded systems typically lack the keyboard, screen, discs, printers, and other recognizable I/O devices of a personal computer. They may also be devoid of all forms of human interaction hardware.
If field-programmable devices are used on a microcontroller, late factory changes to items that have been produced but haven’t yet shipped may be possible. Additionally, programmed memory shortens the lead time needed for the launch of a new product. It may be cost-effective to use parts that are programmed at the time of manufacture when hundreds of thousands of identical devices are needed. The programme is laid out in these “mask programmed” regions at the same time as the chip’s logic. Since it would be expensive to furnish a system with extra, expandable storage, micro-controller programmes typically have to fit in the available on-chip memory. Both assembly language and high-level code are translated using compilers and assembly lines into a little machine code that may be stored in the microcontroller’s memory. The programme memory may be easily removable read-only memory, field-alterable flash, or persistent, read-only memory that can only be programmed at the manufacturer, depending on the device.
Numerous embedded systems require the ability to read analogue signals from sensors. This is what an analog-to-digital converter is used for (ADC). Analog signals that may be supplied to a processor by a device are useless since processors are designed to understand and handle digital data, or 1s and 0s. In order to transform the incoming data into a format that the processor can understand, an analogue to digital converter is employed. A digital-to-analog converter (DAC), which is a less common function on some microcontrollers, enables the processor to produce analogue signals or voltage levels.
The architecture of microcontrollers varies greatly. In some designs, the ROM, RAM, or I/O functionalities are incorporated into the package along with one or more general-purpose CPU cores. Others have been specifically created for control applications. In order to reduce the size of control programmes, a microcontroller’s instruction set typically contains a large number of instructions for bit manipulation (bit-wise operations). To test a bit in a register and branch if the bit is set, for instance, a general-purpose processor might need several instructions, whereas a micro-controller might just need one instruction to do the same frequently needed operation. Since most microcontrollers lack a math coprocessor, floating-point arithmetic is often carried out by software. But some current architectures do have FPU and DSP optimization features. The PIC32 MIPS-based series by Microchip is one illustration.
Microcontrollers are required to respond to events in the embedded system they are managing in real-time (predictable, but not necessarily quick). An interrupt system can alert the processor to stop processing the current instruction sequence in response to certain events and start an interrupt service routine, which will handle any processing that is necessary in response to the interrupt’s source, before returning to the original instruction sequence. Interrupts can also rouse a microcontroller from a low-power sleep mode, where the processor is suspended until forced to act by a peripheral event, which is crucial here because power consumption is critical, as in battery-powered devices.