The mother of all sub-$1 microcontroller comparisons.
I like to think of myself as the King of Cataloguing and Comparing, but I am also happy to share the glory, or in this case, completely cede it.
Reader Jay Carlson has composed a massive missive comparing 21 sub-$1 microcontrollers, and it’s glorious. Not just a simple look at chip specs, Jay dives deep into performance, and perhaps most importantly, ecosystems, devboards, and devtools. After all, any reasonably experienced engineer can get a handle on the hardware by scanning the datasheet, but the knowledge gleaned from spending a day or three with the devtools? Priceless.
Plus, this information will be applicable to higher-end processors too.
I didn’t read every word of the article, but I did notice one small item I’d like to rectify. Jay says:
Old-timers associate the 8051 with “old and slow” because the original was a 12T microcontroller — each machine cycle took 12 clock cycles to complete. Since there was no pipelining, every instruction byte took a machine cycle to fetch, plus one or more additional machine cycles to execute — altogether, it could take more than 50 clock cycles to execute a given instruction. Ouch.
I have to disagree. The 8051 was a minor miracle when it appeared in 1980. I don’t recall anyone thinking it was slow. In fact, most instructions executed in 1µs – faster than a Z-80 for the most part. Plus…hardware multiply and divide!?! In a microcontroller?!? Wow. It’s irrelevant that 12 clock cycles went by in that microsecond.
I did a “similar” comparison to Jay’s about seven years ago – though spanning a wider price range – when I needed to select a very low-end part for a very cost-sensitive project. It’s not nearly as thorough, but perhaps still of some interest.
And Jay, next time you have an idea for a project like this, get in touch! EDN would be happy to run it.
—Michael Dunn is Editor in Chief at EDN with several decades of electronic design experience in various areas.