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There are numerous MCU platforms and once somebody has gotten used to one, they are generally reluctant to switch to another platform.
My question is: If one started using a MCU for general purpose tasks today, how would one go about choosing one? What are the unique selling points of the different platforms?
A year go, I gave a talk on the subject of picking microcontrollers (it took about 1.5 hours). The audience were high-level software programmers and makers. Majority of the audience didn't have prior μC experience, the remainder has played with Arduino only. The head count in the audience was about 30. So, this was a multicast, as opposed to a one-on-one clinic.
The key slide in the talk was this:
Dimensions
for comparing microcontrollers. The list is in descending order.
- Development environment (tool chain)
- Development environment
- Did I mention development environment?
- Support
- Application notes
- Peer support: tribal knowledge, friends, forums, teh codes [sic]
- Features
- Memory
- Peripherals
- Computation prowess
- Power consumption
- Cost
p.s.
I should define the scope which this answer of mine is limited to. I see this platform selection question through two kinds of lens. The first one is a prototyper. The second one is a developer of professional equipment with street prices on the order of $3k and quantities in hundreds a year. The hobbyist lens is not far off too. In these cases, the incremental cost of the microcontroller is small, compare to the cost of development, or to the cost of the professional equipment into which the microcontroller goes.
There is, of course, a very different perspective of mass production. When somebody chooses a microcontroller for a cheap device which will be produced in large quantities (mainstream toys are a good example), they will be driven by the cost of hardware. A modest saving in the hardware cost multiplied by a large production volume (in hundreds of thousands or more) may justify the pain of using an unwieldy development environment and a bargain priced microcontroller with a mediochre support.
Since this question has not quite produced the platform comparison I was hoping for, I have attempted to create one myself by studying the literature as well as the other answers. Maybe this can help somebody else in future.
Please let me know if there are any mistakes or if there is information I can add.
Notes regarding the comparison:
PIC:
AVR:
Arm Cortex-M:
PSoc: (from Rocketmagnet's answer)
Propeller: (from Rocketmagnet's answer)
USB:
"Legend" for the list below:
Properties of least expensive device: (in approx. order of price)
Ethernet:
Your choice of MCU depends a lot on the kind of projects you're going to be working on. Are you making high-volume, super-cheap and simple devices like flashing bike lights? Are you developing complex prototype robots which have to deal with numerous bizarre IO devices and sensors?
I mostly work on the latter. The main problem for me is trying to find microcontrollers which have the peripheral set I want. This is very difficult as our requirements don't seem to be mainstream. We want things like 5 PWM channels, 5 Quadrature decoders, 2 non-standard SPI ports and a UART with negated IO.
The only MCUs I have seen which can handle those kind of requirements with ease are the PSoC and the Propeller.
The Propeller is basically eight 32-bit MCUs in a single chip. If you want some type of peripheral, you simply program one of the MCUs to perform that job. So you can have whatever you want.
The PSoCs come on two flavours, 3 and 5. The 3 is an 8051 core, and the 5 is an ARM cortex M3. Also included on the chip are re-configurable digital and analogue blocks which can be made into a wide range of peripherals: ADCs, filters, op-amps, DACs, SPI, UART, quadrature decoder, CRC generator, etc.
The development environment is fantastic. You have the usual source code editing of a typical IDE, but you also have a schematic editor. You can literally wire up any digital circuit you like, connecting up the peripherals with gates, flipflops, etc. Need 5 PWMs? Easy, just put them into the schematic, wire them up, and away you go. You can even write your own peripherals in Verilog if you want something that's not provided. A great deal of your application can simply be implemented in this sort of hardware.
The real benefit is that you can stick with one chip, knowing that it can tackle a great many of the projects you'll want to do in the future. What I found annoying about PICs was constantly trawling through dozens of devices looking for the one which had the particular peripheral set I needed. Now I don't have that problem.
For me the most important requirement was if the device / the IDE is well supported on my non-Windows PC (Linux). Turned out that for me Atmel AVR's had better (open source) support than PIC.
Using more than one platform is okay. Selecting the best one for each job and also availability of code and examples related to the job.
Most of them have good development tools, arduino has visual studio, pic has a great tool and so do others. So, for me, it is how quickly and easily can I get the job done well, + how many open source people working on the same thing?
Microcontrollers are a fast changing world, there are many advantages of learning on the current "in" chips and most popular IDE's most notable is getting help from the community. As a PIC person I would say the Aduino probably has the best IDE and development boards for newbies at the moment and you can add a lot to a basic aduino board without touching a soldering iron.
Anyone using an aduino for real life stuff may soon want to move on but by that time you will have learnt a lot of basic digital electronics and a good sub-set of C to easily use something more suitable.
As someone has mentioned you choose the chip for your project, I have seen a few projects using ARM chips as simple temperature sensors or AD converters, same way I have seen aduinos and PIC 16's pushed to their limit to generate a space invaders game, FPGA's are galso reat and its good to understand HDL if your seriously going into electronics design.. but unfortunately there are not many projects out there in the real world where you will need to use one most jobs are low volume, rapid design and price constrained and this is where the 8 bit uC reigns supreme
Since many of the posted answers focus on hobbyist use, here comes various recommendations directed to professional developers only.
Bare minimum requirements
If the MCU doesn't fulfil all of these, it shouldn't be used.
Warning signs - MCU hardware
These are things you shouldn't waste time with in the year 2019.
int, which in turn comes with all hidden dangers of C language integer promotions.Warning signs - tool chain
If you are going for a general purpose tasks which can have analog and digital processing then I would have preferred PSoC for its IDE, Debugger and sheer number of things you can do with those.
I have used PSoC3 in college for my projects and it is quite simple to master. Only thing is if you need some performance chips, you'll still need to get them separately. It has good enough ports. So if you are looking some performance chips along with development kit, better go for separate components.
