Microcontrollers are like small computers that can carry out small programs and are often used for automation and robotics. The most popular to those who are just starting out are 8 bit and 16 bit microcontrollers. The main difference between 8 bit and 16 bit microcontrollers is the width of the data pipe. As you may have already deduced, an 8 bit microcontroller has an 8 bit data pipe while a 16 bit microcontroller has a 16 bit data pipe.
This fundamental difference between 8 bit and 16 bit microcontrollers is felt during mathematical operations. A 16 bit number gives you a lot more precision than 8 bit numbers. Although relatively rare, using an 8 bit microcontroller may not suffice the required accuracy of the application. 16 bit microcontrollers are also more efficient in processing math operations on numbers that are longer than 8 bits. A 16 bit microcontroller can automatically operate on two 16 bit numbers, like the common definition of an integer. But when you are using an 8 bit microcontroller, the process is not as straightforward. The functions implemented to operate on such numbers will take additional cycles. Depending on how processing intensive your application is and on how many calculations you do, this may affect the performance of the circuit.
Another key difference between 8 bit and 16 bit microcontrollers is in their timers. 8 bit microcontrollers can only use 8 bits, resulting in a final range of 0x00 – 0xFF (0-255) every cycle. In contrast, 16 bit microcontrollers, with its 16 bit data width, has a range of 0x0000 – 0xFFFF (0-65535) for every cycle. A longer timer maximum value can surely come in handy in certain applications and circuits.
Initially, the price of 16 bit microcontrollers was way above that of 8 bit microcontrollers. But as time progressed and designs improved, the price of 8 bit and 16 bit microcontrollers has reduced quite a lot. 8 bit microcontrollers can be purchased dirt cheap. While 16 bit microcontroller cost more, prices tend to vary a lot depending on the features that are included in the microcontroller.
Summary:
16 bit microcontrollers have twice as long data pipe than the 8 bit microcontroller
16 bit microcontrollers are more accurate at math than
16 bit microcontrollers are more efficient than 8 bit microcontrollers in math operation greater than 8 bits
16 bit microcontrollers have longer timers than 8 bit microcontrollers
16 bit microcontrollers are slightly more expensive than 8 bit microcontrollers