NUREMBERG, Germany – Freescale Semiconductor is preparing for what it thinks will be the next driver of microcontroller sales, the Internet of Things (IoT), with the introduction of a 32-bit microcontroller measuring just 1.9-mm by 2.0-mm. That's the not the die size but the complete Kinetis KL02 MCU--in its chip-scale packaging.
The company is working to support such small MCUs with a local, ultra-low-power radio unit that will start as a stand-alone device but which could be integrated system-in-package or even monolithically.
Speaking at the Embedded World exhibition, Geoff Lees, senior vice president at Freescale responsible for i.MX and Kinetis microcontrollers, said that the company would be "aiming products at consumer and industrial applications and trying to reach a much broader customer base." He added: "We see the internet of things as the next big driver of microcontrollers."
The KL02 contains a 48-MHz ARM Cortex-M0+ core with 1.7 to 3.6 volt operation. There is 32-kbytes of on-chip flash memory and 4kbytes of SRAM together with a 12-bit analog-to-digital converter. Freescale claims the KL02 is 25 percent smaller than the next smallest ARM microcontroller and holds great potential for small form factor applications such as consumer devices, remote sensing nodes, wearable devices and ingestible healthcare sensing. At the same time space-constrained applications that previously couldn't include an MCU can now be upgraded.
The KL02 is a wafer-level chip-scale package wherein the die is connected directly to the solder ball interconnects and, in turn, to the printed circuit board (PCB). This removes the need for bond wires or interposer connections, which minimizes die-to-PCB inductance and improves thermal conduction and package durability for physically harsh environments. The KL02 device is the third CSP MCU in the Kinetis portfolio, and CSP MCUs with increased performance, memory and feature options are planned throughout 2013.
"A lot of our business will be based on chip-scale packaging and we can also put multiple chips, passives and discrete in chip-scale packaging," said Lees.
When asked if Freescale would be embedding an RF transceiver in chip-scale packaging Lees said Freescale is working on a multi-mode radio in a 90-nm manufacturing process. Designed to operate on a 2.4-GHz carrier it would cover Bluetooth and ZigBee standards but not Wi-Fi IEEE802.11. Lees argued that such a broadband radio does not really address the same IoT applications Bluetooth and ZigBee.
Lees said he expected Freescale to be sampling the mixed-mode RF by mid-2013 and an integrated multi-die component including MCU and RF before the end of 2013.
If you were designing a single product for today, then 8 or 16 bit may be fine. If you are starting out in the architectural decision stage of a project targeting Internet connectivity of some sort, then would you really want to have the potential to be hobbled by an 8 or 16 bit architecture?
Comparatively, a 16 bit architecture is going to offer limited code advantage over 32 bit ARM and with expected die shrinks over time, that pretty much goes away.
With 8 bits you will be quickly running into performance issues not to mention limited off the shelf support in terms of software IP (stacks, etc.)
Add in potential time to market advantages from common tool chains and you have what is likely the best architecture for the targeted market.
In my opinion " Why does it need ... ?" is the wrong question. I prefer the "Is it more economical to ... ?" pattern.
One big cost driver here in Europe and I think also in the USA and Japan are human resources. The big human resource specific advantage of the ARM eco system is, ARM M*, R* and A* all share the same ISA concepts and the same tool chain. As a result teaching/learning efforts are minimized.
I'm very interested in knowing the power consumption and more importantly, the operating condition. 32kB flash and 4kB SRAM do not sound a lot. I've the same thought as Daleste. For the application areas mentioned in the article, I feel like 16bits might very much be enough.