The low power computer has arrived. Dell is making low power servers, Samsung smartphones have quad-core CPUs and iPads are disrupting the enterprise.
Understanding what is inside a product like an Android tablet is hard enough, let alone understanding how it was designed, manufactured, distributed and serviced. Here’s a quick rundown of a few of the building blocks and how they fit together. And, of course, this being a deeply techie area, there are many TLAs (Three Letter Acronyms) along the way.
From microprocessor to consumer product
- The ARM Holdings company designs microprocessors.
- Semiconductor foundries make SOCs (System On a Chip) using ARM designs.
- SBC (Single Board Computer) builders make little boards using SOCs.
- Product manufacturers make finished products using SBCs.
- Product vendors make branded products using these finished products.
It’s a division of labour that passes the buck for the really complicated bit - the microprocessor design - back to ARM.
Just about all the low power microprocessors in the world follow designs produced by the ARM company. They design microprocessors and license others to build them. ARM have a few ranges for different purposes.
- The Cortex-A series are the lower power SoC designs for consumer goods. This range of products includes the high-performance Cortex-A15, the scalable Cortex-A9, and the high-efficiency Cortex-A7. Manufacturers love the Cortex-A8.
- The Cortex-R series is for real-time computing. These chips are designed to be good for cameras, disk drives, and routers.
- The Cortex-M series are aimed at the control systems found in washing machines, cars, and joypads.
The current Cortex series is based on a high-level architecture named ARMv7.
ARM makes money by licensing its designs. Some companies get an architectural license then design their own microprocessor cores. Others get a license to use one of ARM’s microprocessor core designs.
ARM Classic processors (that’s the older, slower, and uglier generation) have been an outstanding success. 15 billion of these processors have been shipped. There are three ranges of microprocessor designs, called ARM7 (found in iPods, Nokia phones, and Nintendo games consoles), ARM9 (found in the Squeezebox music player, Seagate storage, and HTC phones) and ARM11 (found in Kindles, iPhones, and the Raspberry Pi). Some of these classic designs are obsolete and others are used in new products.
The chip architecture that ARM based these classic ranges on evolved over time. The ARM7 and ARM9 chips are based on the same architecture, called ARMv5. The ARM11 is based on ARMv6 architecture. It is a naming strategy that’s a little confusing.
SOC (System On a Chip)
Semiconductor foundries - the chip builders - could build the microprocessor as one discrete chip, but they often bundle it up in a bigger chip called an SOC (System On a Chip).
The SOC contains the microprocessor and as many other building blocks as will fit.
- An SOC for a TV may include a GPU.
- An SOC for a mobile phone may include a radio baseband processor.
- An SOC for home storage may have Ethernet and SATA interfaces.
Often the company that designs an SOC is not the company that builds it. As with building cars, once upon a time vast factories did everything. Now different processes have been split up between specialist companies.
The Marvell Technology Group designed an SOC called the Marvell Kirkwood 88F6281, using an ARMv5 architecture for the microprocessor part. Marvell didn’t build this SOC because Marvell are a fabless semiconductor company. The fabless word means they don’t fabricate (or build) semiconductors. Marvell outsourced the build of this Kirkwood SOC to its business partners.
SBC (Single Board Computer)
The manufacturers of SBCs (Single Board Computers) buy these SOCs. An SOC is added to a board along with anything that couldn’t be crammed into the SOC, such as even more memory, power management units and interface sockets.
The manufacturer of an SBC has plenty of jobs to do, such as:
- designing its PCB (Printed Circuit Board),
- tweaking drivers so it will work with popular operating systems, and
- knocking up quick prototypes.
The Arduino is an SBC designed to teach electronics to non-technical students, and has caught hobbyists’ attention around the world.
The Cloud Engines Pogoplug storage server contains a SheevaPlug SBC, which in turn contains a Marvell Kirkwood SOC.
These SBCs are purchased by product manufacturers. These guys are left with the less technically excruciating work of finishing the consumer product by adding the remaining parts: perhaps some IO connectors, a touchscreen, a battery, and an enclosure.
An ODM (Original Design Manufacturer) manages the whole process of building chips, designing SBCs and shipping the finished product back to the customer. Foxconn is the ODM for Apple, building its iPhone and iPad products.
Finally a company buys lots of the finished products, dresses each one in its livery and sells it under their name to a consumer.