8-bit microcontrollers are alive and kicking

February 23, 2017

Max The Magnificent-February 23, 2017

One talk I always enjoy giving is called Not Your Grandmother's Embedded Systems. This is an ever-evolving presentation that changes to accommodate new technologies and products as they leap into the limelight, but the overall flow is as follows: we begin by defining what we mean by the term "embedded system" (if we can’t agree on this, there's little hope for the rest of the talk); next, we consider how technology has evolved over the past 100 years; finally, we look at some of the state-of-the art technologies and products that are only just starting to appear on the scene.

To provide a little break in the middle of the presentation, I tell the audience that the following few slides will show what we can expect to meet in embedded space (where no one can hear you scream) in the next 10, 20, 50, and 100 years. This is obviously a bit of a joke, because things are moving so quickly these days that I would be hesitant to make predictions as far as five years out. The point is that the first item on each of the +10, +20, +50, and +100 year slides says: "Experts predict the demise of 8-bit MCUs."

This always goes down well with an engineering audience because they've been hearing this prediction for decades now, yet 8-bit MCUs continue to march on. Of course, some tasks demand 16-bit and 32-bit processors, but there are myriad applications for which small footprint, low-cost, low-power 8-bit MCUs are ideal, including consumer (e.g., remote controls, thermostats, computing/printing), industrial and automotive (e.g., security systems, sensor nodes, smoke detectors, alarm systems), and general-purpose functions (e.g., system monitoring, motor control).

The reason I'm waffling on about this here is that Microchip has just announced its PIC16F15386 family of 8-bit MCUs. Available in a selection of different packaging options with anywhere from 8 to 48 pins, these devices offer up to 28 KB Flash and 2 KB RAM; four 10-bit PWMs; two capture, compare, PWMs (CCP); up to two comparators; a 10-bit ADC (up to 43 channels); a 5-bit DAC; SPI/I2C and EUSART communications functions; and they also include Microchip's Core Independent Peripherals (CIPs).

While I'm thinking about it, Microchip is also giving away a very tasty little development board that's FREE (while supplies last).


Free dev board while supplies last (Source: Microchip Technology)

When I cast my mind back to the 8-bit MCUs of my youth, I find it difficult to believe how much functionality and capability their modern descendants offer. Take the core independent peripherals, for example. These can be interconnected to allow the near-zero-latency sharing of data, logic inputs, and analog signals without additional code or the need to interrupt the CPU, thereby freeing the CPU to perform other tasks and reducing Flash memory consumption.

When it comes to programming, you can use the downloadable MPLAB X IDE and/or the quick-start cloud-based MPLAB Xpress IDE. In both cases, you can also use the MPLAB Code Configurator (MCC), which is a free software plug-in that provides an intuitive graphical user interface (GUI) to configure peripherals and functions specific to your application without having to peruse and ponder countless mind-numbing datasheets.

For more information, bounce over to the PIC16F15386 family product page. Of particular interest (at least, to me) are the descriptions we find there of the various building blocks available to us, including the Zero Cross Detect (ZCD) module, the Complementary Waveform Generator (CWG), the Numerically Controlled Oscillator (NCO), the Hardware Limit Timer (HLT), and the Peripheral Pin Select (PPS) capability.

So, what do you think? Are you of the opinion that the age of 8-bit MCUs has been and gone? Or, like me, do you believe that these little beauties will provide the brains to power a wide range of embedded systems for decades to come?

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