No, this isn’t another “Is 8-bit dead?” or “When will we see the last of 8-bit?” column. Frankly, I’m tired of that discussion, as it’s clear there is no end in sight for 8-bit MCUs. So let’s discuss them like we talk about any other new technology when innovation occurs. Yes, innovation is still occurring in 8-bit.
The primary reasons for designing a system around an 8-bit processor are still there. One is the complexity, or lack thereof. Second is that there’s usually no need for an operating system. And third, which is likely the number one reason to go with an 8-bit MCU, is the cost. The chips are still (and likely will remain) under $1, and in some cases, significantly below.
I recently heard about a new 8-bit development that really intrigued me. Microchip‘s latest 8-bit offering is designed with “core independent peripherals.” This is a fairly common feature of 32-bit processors, but isn’t typically found on 8-bit devices. The PIC16F161X family (I never understood why they designated the 8-bit parts with a “16″) employs hardware-based peripherals that can offload timing-critical and core-intensive functions from the CPU, allowing it to focus on other critical tasks within the system. The peripherals reduce system complexity by eliminating the need for additional code and external components to perform a set of fixed functions.
One of the included functions is a math accelerator with proportional integral derivative (PID), offering core-independent calculations, and the ability to perform 16-bit math and PID operations. Another function is the angular timer, which is a hardware module that calculates the rotational angle in functions like motor control. Regardless of speed, the timer allows recurring interrupts at a specific rotational or sinusoidal angle without using the core’s computation. A 24-bit signal measurement timer performs high-resolution digital signal measurements in hardware, resulting in more precise and accurate measurements.
Did I mention that these parts sell for 53 cents in large volumes? You gotta love 8 bits.