Comment by emctech
8 days ago
This line of micros has been out for almost 2 years now but they only just took the 1.38mm^2 package out of pre-production. I started a design last year of a tiny earring with ~102 addressable LEDs on it, a microphone, a bunch of supporting circuitry and this micro. https://i.ibb.co/JWh57LLw/IMG-20260408-183807502-HDR.jpg Unfortunately by the time I was ready to order the boards I found the tiny package was unobtanium and had to resort to the second smallest package which isn't very small. Frustration!
Not worth changing the design now...
And for people saying it is low on RAM and flash, you need to understand this is a low cost micro. You can also do a lot of work with a small amount of RAM by managing your memory manually. Through the use of C unions I have about 3kB worth of variables that get switched in and out depending on the mode we are in. I have enough space to record analog audio samples and perform a fourier transform over the samples and use the generated to data to drive algorithmically generated animations on the LED array.
You might enjoy this dime-sized earring I designed ~13 years ago - https://www.youtube.com/watch?v=XyBhdRp_5rY
How did you power it?
tiny coin cell, would run for about six hours
very cool!
Not trying to be pedantic, but it was released back in March last year 2025 [1].
It will be much better if the OP link to the announcement news rather than straight to the datasheet for better context.
[1] TI introduces the world's smallest MCU, enabling innovation in the tiniest of applications:
https://www.ti.com/about-ti/newsroom/news-releases/2025/2025...
You are right. I am just a little salty that it took them so long to have the smallest package available.
My sleeper pick for a design like this was JL700N series. Intended for cheap TWS, ultra high integration. 3x3mm QFN20 package, and in it: BLE, USB, can be powered off 5v or 3.3v, built in battery support complete with a charger, almost no passives required. SDK was a bitch though.
There are more pieces like this in "wearables" market now, things like "SmartBond" series. But for a while, weird off-label pieces like this wore the integration crown.
Wearable MCU is sometime stupidly good. Recently i learned that the new Pepple watch use SF32lb55. It has dual mode bluetooth with LE Audio, all the fancy like pmic, battery charger, usb, 2.5D GPU etc, it also has insanely large memory(16MB flash/8MB PSRAM on some packages). The whole MCU costs like $3.
If you dive into even more niche, NDA-Only MCU, We have BES2700 MCU, which is even better
These earrings look awesome btw!
Thank you! I want to try and sell them but I just have a few bugs to squash and to finish off the mechanical design of the charging cradle.
Have you blogged about the earrings perchance? They really do look great, and I'd love to see some details of your process.
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Earrings with microphones, another thing for privacy nerds to lose sleep over. Cool board though!