Just what the world needs: another 32bit microcontroller

5 November 2007

Microchip Technology, the company that stole the lead in 8bit microcontrollers from Freescale Semiconductor (back in the days when it was part of Motorola), is now going to have a go at the 32bit market. The company has licensed the M4K core from MIPS Technologies rather than give any of its own architectures another workover. Two years ago, the company turned its digital signal processors into general-purpose microcontrollers to try to break into the 16bit market. Now it has another architecture to push.

What does it mean? Basically, the decision provides designers inundated with choices of low- to mid-range 32bit micros with...more choice. Yay.

Now, this is a stunt that Microchip has pulled off once before. But only once. If you rewind time by about 12 years, you can look at the circumstances that gave an aggressive relative newcomer the advantage over a seemingly unassailable market leader. The problem is that, this time around, the circumstances are different. And Microchip has yet to demonstrate that it can turn success in the 8bit market into big sales in the 16bit sector, let alone the even more competitive 32bit space: a market space that a number of chipmakers have made the battleground for control of the future microcontroller business. And they all started earlier.

On the face of it, the M4K core selected by Microchip has everything a 32bit microcontroller user could want. Access to compilers and other tools? Check. Code compression? Check. Fancy-schmancy register banking or shadow register scheme that nobody ever really uses because operating systems don't support it and it takes too much time to set up manually? Check.

There is very little in the MIPS M4K that cannot be found elsewhere. However, that is true of most of the 32bit players - their cores pretty much do the same thing.

However, that was the case in the mid-1990s when Microchip began to catch up and overtake Motorola. What Microchip did different came down to two things: software and memory. And a boom-bust cycle that the semiconductor never really recovered from.

In 1995, Motorola was riding high, along with the other chipmakers. After a long recession, the chipmakers were selling everything they could make. And then some. Fab capacity was so short that some foundries were booking the same wafers twice, with disastrous consequences for whoever turned out to be the loser. Motorola found itself with the situation that it could not possibly provide 8bit microcontrollers to everyone who wanted one. Some customers were put "on allocation", which is industry code for "you're not getting any more for a while".

If you were in Motorola's position, what would you do? Who would you keep happy? The big guys, of course. And that's what they did. Smaller customers were turned away and so they looked for alternatives. As a company that was still recovering from a near-death experience in the late 1980s, Microchip had some spare capacity. But, more importantly, it had alighted on a sales strategy that not only won customers, it kept them.

It's hard to believe that people once argued over this point, but the ace that Microchip held was that it would sell programmable parts for about the same as those that had to be programmed at the fab. To justify this mask programming, you needed to order a lot of parts. And you had to get the order right as you could be in for a long wait if you found out sales were better than expected. Or you wound up with a lot of spare chips.

The advantage of mask program memory over one-time programmable is that it's cheaper to make. A mask memory is basically a matrix of wires: connections between them define ones and zeroes. You use a mask to define where those connections are. One-time programmable, on the other hand, needs a special kind of transistor. The result is that it takes more steps to make and works out bigger.

Incumbent microcontroller suppliers were loathe to provide parity between mask and one-time programmable devices even though the processes needed to manage those masks became increasingly burdensome. Microchip had no such qualms. So, once customers moved from their traditional supplier, they found they liked the new environment.

On top of that, Microchip made sure the tools they used to develop software were not too expensive. This encouraged very small companies and consultancies to use Microchip rather than anyone else, as the competition liked to charge as much as they could for the privilege of using their tools. Or they had to go to third-party suppliers who could not defray the software costs against silicon sales.

The strategy was so successful that a number of players have tried to emulate it since, at least in terms of software tools. It also means incumbent players are wise to the techniques used last time around. Cheap tools are not exactly rare in the 32bit space. In fact, you can get quite a lot for nothing, thanks to the Gnu and Eclipse efforts.

Memory is likely to play a part in the 32bit market. But Microchip does not have much in the way of cards to play here. Anyone who is serious about selling 32bit microcontrollers knows that they have to offer fairly serious quantities of flash and static memory to get anywhere. That is part of the reason why the processor core itself is not all that relevant. It comes down to how much you can use manufacturing decisions to push memory costs. The quantities of memory involved mean that these devices tend to look like memory chips with a processor core and some peripherals bolted onto the side.

This is where Microchip may end up being outpaced by companies already in the market. The Arizona-based chipmaker has chosen to go with TSMC's 0.18µm process – the company does not currently have any fabs able to deal with a sub-0.35µm process – whereas some competitors have decided to push density by moving to 0.13µm. Infineon Technologies in particular has a tactical advantage here as the company has had a working flash module on 0.13µm for several years. The foundries are catching up but, when it comes to pushing costs on what are becoming mature processes, the integrated device manufacturers tend to have more room to manoeuvre on price. Many of Microchip's competitors are sticking with 0.18µm for the moment, so Microchip is not that far behind in terms of process. But neither is it ahead.

And the company is coming into this market well behind Renesas, NEC and Freescale as well as ARM licensees such as Texas Instruments. And both microcontroller-oriented ARM cores – the ARM7 and the M3 – have picked up wide support among other chipmakers.

ARM has a distinct advantage if you take social factors into account. A lot of people who have migrated to 32bit from 8bit are picking ARM because it looks to be one of the dominant embedded-processor architectures of the early 21st century, similar to the way that Motorola dominated the 1980s and 1990s with its 68K family. Those social factors are hard to ignore - engineers are well aware that there are plenty of job ads for people with ARM experience. ARM's position in the mobile-phone and handheld market is paying off well here.

By opting for MIPS, Microchip does not have to compete head-to-head with so many players. But neither does it get the opportunity to pick up on customers who have embraced ARM because there is plenty of competition and plenty of engineering talent around for it.

It makes it look as though Microchip's position is more defensive than aggressive. If it cannot stop people moving to 32bit, at least get them to migrate to a 32bit micro supported by the same family of tools. But it's hard to be more optimistic about Microchip's chances than that, especially given the company's slow progress with non-8bit products in the past.

History does not look as though it is going to repeat itself in the 32bit microcontroller space.