[matthewvia]

I appreciate that FPGAs are certainly one way of doing this, and your point are valid, but I respectfully disagree that it is an overall better approach. FPGAs are more expensive than these microcontrollers, are a separate device to program, and now mean you have to maintain both software and RTL together. I also don't believe that any of the issues you describe are very difficult to do in pure software:

- reconfigurable pinouts, why is gpio muxes not the same? I understand that if you want to be extremely flexible with pwm'ing peak and hold injectors, that is probably easier with an intermediate hardware interface, but all the other output settings seem trivial to change in software

- I would argue parallel computation isn't really even necessary. These chips are fast, and the computations aren't that intense. That aside, I personally manage that parallelism by using the dma controller to bitbang outputs

- Chained high resolution timers -- I'm not really sure where you're going with this. I personally dma input capture timestamps, and can't imagine needing more precision.

- PID and other software. If you're talking about an AVR, I completely agree that these chips are largely too anmemic by themselves, and extra hardware would help. A modern cortex m4 or m7, however, has plenty of oomf, and it all goes back to maintainence cost of software vs RTL+software.

Either way, FPGA's are certainly a valid way to solve these problems, but personally I like not being locked into specific hardware arrangements. My design is just a hobby design that nobody should use, but it can easily manage 1/4 uS output precision with plenty of spare cpu capacity.

edit: as an additional aside, its pretty hard to have a free and open source project if you depend on an fpga. The toolchains are all proprietary, which would limit the goals of a project to something like the lattice with the icestorm toolchain.

[asguy]

We can agree to disagree on engineering choices. I've been working on/with aftermarket ECUs for just under 20 years, and I'm sharing with you what I've seen from being "in the trenches".