You'd think that would be a positive? Presumably only a very tiny fraction of those are suitable for automotive applications e.g. also presumably some of those were only made in smaller quantities trying to hook some big customer.
I think we've always had a pretty large variety of microcontrollers, just something like an 8051 was available in hundreds of options from various companies. Microchip has always had lots of different ones with slightly different options. Sometimes (often?) those are the same die in a different package with some different build time options enabled.
I'm not following you how on that would be a positive (in a chip shortage situation).
Say you use 50 microcontrollers in a car. Probably 15+ separate part numbers? One or two of those can't be acquired, so boards need to be redesigned and the production line is held up.
Now, imagine a different world with wide cross-licensing between manufacturers and instead of doing hundreds of separate variants slighly cost optimized for various purposes for each major microcontroller design, let's just have a small number of kitchen sink variants.
If you're one car company or building one car design you try to minimize the number of different components in your design. However, different cars companies might (and do) choose different MCUs based on their architecture requirements. Some car vendors use CAN bus, so they'd pick a microcontroller with CAN. Some use Ethernet. They have tools and software the generally is build for certain families. An ECU is not going to have the same CPU as the radio or the entertainment system, it just doesn't make sense.
The diversity should mean that when Audi picked some specific microcontroller for their ECU there's not too many others that are using the same part at volume. So this should isolate them to some degree from fluctuation in demand. If there's only one vendor/part, like we're seeing with GPUs, then nobody can get any, period. Even if Audi can't get their CPU for some reason then GM who uses a different CPU might be able to get it. Well, unless it's the same factor and the fabrication is the bottleneck...
It's a trade-off though, since every one of those controllers will probably be less efficient and more power hungry then more specific parts would have been
I agree that it's a tradeoff, but not in power efficency. It's easy to shut off parts that are not being used.
It's primarily a tradeoff between a) increased chip size, b) number of external chip connections, c) cost, d) probability that having a small number of footprints/designs will help.
So, in short: cost vs winnings from having a lean library of component.
You would have thought that the whole point of microcontrollers was to decrease the number of different chips that have to be manufactured on the basis of them being programmable.
I've used microcontrollers extensively so I'm not just randomly rambling ;)
Here's examples of differences:
- Power consumption (some applications care less, some care more).
- Number of pins. Sometimes you just need one input and one output, shoving a high pin count device in there doesn't make sense.
- Pin functions. Higher current capability or other specialized functions like A/Ds D/As etc.
- On-board peripherals. Some microcontrollers have on-board motor controllers, networking, specialized counter hardware, real time clocks, DSP blocks etc.
- Integrated memory and types of memory.
- Oscillator options/frequencies.
Add to that all the different CPU architectures and vendors.
It's more like the microcontroller replaces a bunch of chips or custom chips in certain applications. It's less like you can build one microcontroller to rule them all. Those are still generally mass produced devices so there's really not a lot of economy of scale, i.e. the one micro to do everything (if that was even possible, which it is not) would just be more expensive and less optimized.
I think we've always had a pretty large variety of microcontrollers, just something like an 8051 was available in hundreds of options from various companies. Microchip has always had lots of different ones with slightly different options. Sometimes (often?) those are the same die in a different package with some different build time options enabled.