alt Hacker News> What does a cheap microcontroller core need? Let's inspect what they are used for. Typical use cases are to interface with and quickly reconfigure hardware blocks in a larger chip, eg in an MP3 player, an SD card, or a USB stick. The hard work is done by custom IP and the CPU core is just there to occasionally prod a register or configure something.
This is not the only reason to use a microcontroller or 75% of microcontroller vendor (e.g. STM) offerings would have no customers. Not everyone has custom IP that does all the work either, that’s actually fairly rare. It’s odd to pigeonhole microcontrollers like this just to go on a fairly lengthy rant about interrupt latency as if that somehow makes RISC-V unsuitable to what is an incredibly diverse application space. Maybe the rest of their post has better arguments, but I’m not impressed enough by the first one to keep reading.
This is a "microcontroller core", not a "microcontroller".
We're talking "deep embedded" applications - where an ASIC is designed for a very specific purpose, and that design just so happens to call for a programmable CPU core to be included in it.
This is the kind of design that lives in your keyboard, your mouse, your USB stick, your USB hub, your HDD, your SSD, your eMMC chip, your memory card and more. Remember: you're never more than 3 meters away from an 8051 core.
I do agree that most of this piece is nitpicking - poking at ultra low level things that are largely irrelevant to the tried and true "deep embedded" exercise of Just Ship It.
No one really gives a shit if an operation takes one instructions or two, or which instruction sets are consistently present in different cores. What "deep embedded" people give a shit about is not having to work with ancient 8051 tooling and 8 bit ALUs and memory banked 64kb spaces while writing code for the one core they happen to actually have. And RISC-V got that. The piece actually agrees with that sentiment.