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1.38 Millimeter Microcontroller

ti.com

71–80 of 106 posts

Re: 1.38 Millimeter Microcontroller

#71
post #53
post #34

At $0.20 in 1k quantities, this is TI's answer to the CH32V003, Puya PY32, and the STM32C0 series. It's great to see tier-1 silicon vendors participating in the race to the bottom for jellybean microcontrollers. The 1KB of SRAM is admittedly very tight (even WCH's 10-cent RISC-V parts usually give you 2KB), so you are strictly in bare-metal, carefully-managing-your-stack territory.

1KB isn't so bad unless you are making something complicated or need large buffers. You can do quite a bit of nontrivial stuff with it. Years ago I made universal remote with ATtiny13 + external EEPROM for storing remote data. It has only 64 bytes of RAM, that's what I would call very tight. Was still able to program it in C, 1KB flash and number of pins were bigger limiting factor than ram. Plenty of DIY projects us…

It's been long enough ago that I don't use it as an interview answer anymore, but one of the most interesting things I built (technique-wise) was a Z-80 based serial multiplexer with no RAM. The only volatile memory it used was the device registers. The fun part was handling subroutine calls without a stack. The Z-80 has an indexed jump mode, so before calling a subroutine, I'd fill the jump register with the statement after the subroutine call, and when the subroutine was done, execute the jump with the (return) address prefilled.

Anything to save a few bucks on a 6264 SRAM component :-)

Re: 1.38 Millimeter Microcontroller

#72
post #15

Earlier quoted context omitted.

It's got a UART, it's got a PWM, it's really fast, and it's got masses of memory. I'd build a really tiny synthesizer, port my Juno 106 plugin's voice engine to it. But like *really* tiny.

"Masses" of memory, it does not have. Sufficient to the task for synthesis? Maybe, if you do a fair bit of assembly ..

It's got 16kB of flash and 1kB of RAM, that's plenty.

Re: 1.38 Millimeter Microcontroller

#73
post #35
post #15

Earlier quoted context omitted.

"Masses" of memory, it does not have. Sufficient to the task for synthesis? Maybe, if you do a fair bit of assembly ..

I don't know anything about synths, but the M0 architecture is designed to run the program out of flash, I think? So 16KB is quite a bit. 1KB is surely enough to store synthesizer patches. Several, probably.

You need a few dozen bytes of storage per voice, like four bytes for the phase accumulator (uint32_t), another four for the current pitch offset that gets added, and so on.

It all adds up, especially if you want to implement a ladder filter properly.

Re: 1.38 Millimeter Microcontroller

#74
post #36

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 unobtaniu…

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?

Re: 1.38 Millimeter Microcontroller

#75
post #36

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 unobtaniu…

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.

Re: 1.38 Millimeter Microcontroller

#76

A silly question (from a non-HW guy). Why are digital bathroom scales so coarse? Some have a weight resolution of +/- 500 grams. Would a better microcontroller make a weight faster or more presise? I guess this TI micro controller is overkill for a bathroom scale.

I used to have a bathroom scale with a single strain gauge that was accurate. Accurate, as in weigh yourself, pick up a 1lb object, weigh yourself again and see an extra pound. That scale had a "lifetime" nonreplaceable battery in it and after 20 years or so, gave up the ghost. Every scale I've tried since is wildly inaccurate, and they do have brains and they fake it. Step on, get a random weight within a 5lb range…

> Accurate, as in weigh yourself, pick up a 1lb object, weigh yourself again and see an extra pound.

That's resolution (or dynamic range), not accuracy. The scales could be 10lbs off of your weight and still do this.

Re: 1.38 Millimeter Microcontroller

#77
post #59

Earlier quoted context omitted.

Have you blogged about the earrings perchance? They really do look great, and I'd love to see some details of your process.

Yes, I’d love to see a video of them in action.

I don't have a blog post up about them yet, it is in the works. The website is active though: https://www.reactiv.au

Re: 1.38 Millimeter Microcontroller

#78
post #36

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 unobtaniu…

You might enjoy this dime-sized earring I designed ~13 years ago - https://www.youtube.com/watch?v=XyBhdRp_5rY

very cool!

Re: 1.38 Millimeter Microcontroller

#79
post #36

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 unobtaniu…

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 th…

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

Re: 1.38 Millimeter Microcontroller

#80
post #58

Earlier quoted context omitted.

Yes, that's "bare metal" as opposed to programming in MicroPython, Javascript with Espruino, Lua/NodeMCU, Rust, or adding your C application on top of an off-the-shelf RTOS. C support is basically universal these days, very few chips require you to program in only assembly anymore.

Rust compiles to bare metal (assembly aka machine instruction code), just like C does.

In Embedded, it's usually agreed that "Bare Metal" means using no OS, not meaning using low level languages.
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