These days, consumers expect their devices to have exceptional graphics, whether it's their television or the display screen on their wearable fitness device. Thanks to our experiences with smartphones and tablets, like iPads, we've come to expect a high level of quality in displays. As a result, anything that doesn't have a bright, clear and high-resolution graphics display is likely to be viewed as lower quality and undesirable.
Therefore, it's important for designers to put some thought into the graphics microcontroller that they select for their embedded devices. While there are a number of points to consider, typically the first decision to make is whether to use an 8-bit, 16-bit, or 32-bit microcontroller for the LCD graphics display. While the choice might seem obvious sometimes, it isn't always, and making the wrong decision can be disastrous to the success of your project.
8, 16 and 32-Bit Microcontrollers Explained
To begin the discussion of how to choose the right microcontroller, it's useful to briefly explain the differences between each type. Microcontrollers are small computer chips that have an integrated circuit, a processor core, and embedded programmable I/O peripherals.
An 8-bit microcontroller is one that processes data units that are 8 bits wide. This means that your CPU can use an 8-bit data bus or pipe and accesses data by a single device instruction. Because 8-bit microcontrollers transfer data in small amounts at a time, it tends to have slower speeds or more limitations than the larger microcontroller options.
For example, when used in graphic displays (such as during image processing) an 8-bit processor can only display up to 256 colors, while a 16-bit processor allows for several million colors. Depending on the application, this may not matter so much, but if you want clarity and more depth of color in your display, an 8-bit microcontroller may not be the right choice.
A 16-bit microcontroller offers more than just a wider range of colors. A 16-bit unit can process data that is 16 bits wide and therefore requires a 16-bit data bus or pipe. These devices are typically capable of performing more accurate mathematical functions than the 8-bit microcontroller. In addition, 16-bit microcontrollers can handle more than one instruction at once.
Finally, moving up to the 32-bit microcontroller, the capabilities become even more advanced. Not only do 32-bit chips have larger data units, they also allow for faster transmission of data and even more complex mathematical functions. Moreover, 32-bit microcontrollers also contain memory, something that 8-bit controllers do not.
It is also important to note that a 32-bit controller can access a variety of data structures from memory. Whereas, most 8-bit controllers require several different instructions - sometimes up to half a dozen or more - to access data. This allows for faster, more powerful embedded technology and better LCD displays. However, it also requires more power and costs more.
Comparing Different Microcontrollers
Understanding the differences between microcontrollers on a theoretical level is one thing, but the way these differences play out when designing systems for LCD displays is another. For simple displays that do not require color, or that are only displaying a small amount of information (such as a wearable device or a temperature gauge) an 8-bit microcontroller is most likely going to be adequate for the job.
In the past, the main advantage to an 8-bit controller has been its price, but in recent years, the fact that 8-bit microcontrollers tend to lack the memory and power of 16 and 32-bit controllers have negated most of that price value. In fact, most embedded technology today runs on a 16 or 32-bit microcontrollers. In terms of flexibility, 32-bit controllers are the best, thanks to their increased memory, power, and available features and on-chip peripherals.
However, with that increased CPU power and memory also comes greater power consumption. For that reason, some designers opt to go with a 16-bit microcontroller when they don't need all of the features that a 32-bit offers. The 16-bit controller provides more accuracy and reliability than an 8-bit controller, without the expense and power consumption of the 32-bit, making it an ideal component for mid-level applications.
In the end, the decision about which microcontroller to use comes down to the budget, the power needs of the device, and the requirements of the display. It is still best not to assume that one controller is better than the other simply because of its size and feature set. To make the perfect display, a thorough analysis of the needs and requirements of the product must be undertaken to decide which microcontroller will be the perfect fit.
