8 Bit vs. 32 Bit: Which Bit-size is the Superior Choise?

A microcontroller's bit descriptor specifies the amount of data that the chip can work on at one time. For example, an 8-bit device can add two 8-bit values without the need for additional memory (along with a carry bit for the potential overflow).

At any given time, an 8-bit microcontroller processes 8 bits of data. The number of bits used by an MCU (also known as bit depth or data width) indicates the size of the registers (8 bits per register), the number of memory locations (only 28 = 256 addresses), and the greatest numbers that can be processed (again, 28 = 256 integers, or integers 0 through 255). An 8-bit microcontroller has limited addressing, but some 8-bit microcontrollers feature paging, which chooses which onboard memory bank to use based on the contents of a page register.

In theory, a 32-bit microprocessor can handle numbers up to 232. They have arithmetic logic units, registers, and a bus width of 32 bits. In principle, this means that a 32-bit processor can handle four times the quantity of data, making it more data-efficient. Other distinctions between 8-bit and 32-bit microcontrollers exist that go beyond arithmetic operations.

These microcontrollers differ from one another in terms of arithmetic operations. Each type of microcontroller has a unique data set. An 8-bit microcontroller can only manage 0 to 255 bits, and a 32-bit microcontroller can handle 0 to 4,29,49,67,295. When the data width becomes large, the microcontroller's arithmetic core enables the controller to compute a significant quantity of data in a single moment.

It may appear that a 32-bit microcontroller will always be housed in a larger container than an 8-bit microcontroller, however, this is not always the case. The form factor of some 8-bit, 32-bit microcontrollers is the same (e.g., Microchip offers a series of microcontrollers with different bit widths that all come in  TQFP -64 packages). DIP packaging is used for 8-bit microcontrollers, as seen on popular  Arduino boards.

The data types used in your code will also influence which sort of microcontroller to utilize at the software level. An unsigned number defined in an 8-bit microcontroller, for example, will only take up one byte. In a 32-bit microcontroller, the identical variable consumes 4 bytes of data. "Wait, a 32 bit MCU has 16 million times as many addresses; what does it matter if it takes 4 bytes?" you could reply. The maximum number of unique addresses available has nothing to do with the amount of memory available on a microcontroller. Because on-chip memory is often at the KB level, the amount of data necessary in your code is important.

Choosing between an 8-bit and a 32-bit microcontroller includes more than just data width. Understanding the key distinctions between 8-bit and 32-bit microcontrollers can assist you in making the right option for your design.

The fundamentals of embedded system design entail compiling a list of required peripherals based on project specifications. An 8-bit microcontroller would be insufficient if you need  Ethernet, a USB  Stack, several universal asynchronous receiver-transmitter devices (UARTS), and a Controller Area Network (CAN) bus. You may need to consider adding peripheral chips, which may cost more than a 32-bit microcontroller on its own.
In general, 32-bit microcontrollers have more features than 8-bit microcontrollers. A 32-bit microcontroller can efficiently manage several peripherals because of its better processing speed. Keep in mind, however, that 32-bit microcontrollers consume more power, especially when all embedded systems and peripherals are enabled.

To conclude, after discussing the differences between them from different angles, to select the optimum microcontroller for your PCB design while saving time and total cost, carefully weigh the primary benefits and drawbacks of 8-bit vs 32-bit MCU. When selecting the ideal microcontroller for your design, you can avoid choice paralysis and potential setbacks by considering design needs such as speed, complexity, peripherals, and flash memory.