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RV32E seems dead in the water - no value, no movement, no uptake. RV32I* is ... a dumpster fire, and I say this as someone helping shepherd both silicon specifi
by 95014_refugee 4y ago
RV32E seems dead in the water - no value, no movement, no uptake. RV32I* is ... a dumpster fire, and I say this as someone helping shepherd both silicon specification and reusable software components for it. Really basic things like "how interrupts should work" seem to be a matter of personal taste (and the specs are ... awful, like RFC-by-undergrad awful).
By contrast, and for all its faults, AVR is well-defined and stable. This removes a substantial amount of risk from a customer perspective. Once you have attained a basic level of competence in delivering something on AVR (and most major players did this 20 years ago) you can repeat this in a relatively predictable, consistent and low-risk fashion. The same cannot be said of RV32I*, where every new implementation has to be treated as a from-scratch bringup.
Consider the (relative non-)success of AVR32. Not a strict 1:1, but it brought very little to the table in terms of relevance to 8-bit AVR customers, and added a bunch of risk and overhead.
Obviously there are customers for which COGS is king, and they won't be buying AVR. Ditto those where engineering technofetishism is a consideration (gotta motivate your devs, and if new toys are what does it, then you have to factor it into your plans). But there are (clearly, since they keep making money with the product line) others for whom AVR's strengths make good sense.
Switching from AVR to RV32I* would destroy the product line from that perspective. Which is probably not the "opportunity" you were thinking of. 8)
[edit: fix use of *]
- sitkack 4y agoIn one of these micro lines moving to RISCV they can provide a growth path that didn't previously exist. I haven't used a PIC in 10 years, but it seems like an ideal candidate to keep the same foot print and peripherals while moving to RV32IC. The package and peripherals matter a whole lot more than the ISA in a lot of applications. The code is often a while(1) and some interrupt handlers.
- snvzz 4y agoIt is just too new. Remember unprivileged ISA was 20191213 and privileged ISA was 20211203. This is mere months ago. We get some micro-controller families early, and the companies behind them do commit to some level of long term part availability. Recent code density work (Zc etc) enables higher code density than Thumb2, finally making RISC-V the most dense in 32bit too. Furthermore, there's standardization going on for simpler and more complex interrupt controllers, for ISA profiles, and for platforms (e.g. profiles on hardware that's expected to be there), which will make long term part availability less important, by maximizing re-usability across hardware. These early hiccups shouldn't discourage anyone with an ISA this new; Effort is being put into the right places.