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The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

jaycarlson.net

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Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#61

Post by DiabloD3 »

DiabloD3 wrote: post #37

I think he's doing an important analysis, but not for DIY hobbyists: knowing how cheap your SoC is only makes sense when you're finalizing a BOM for mass production, even if they're small runs. The SoC is only one component of at least a dozen required to make a working microcontroller board. If you're doing DIY hobbyist yourself, you'll want to buy pre-mounted SoCs in a known form factor (as in, it is on a tiny daug…

Update: Adafruit sells a RP2040 in a Pro Micro clone for $9: https://www.adafruit.com/product/5302, otherwise seemingly identical as the Sparkfun RP2040 Pro Micro clone.

That makes it about as cheap as real ATmega32u4-based Pro Micros, which are still hard to find due to the chip crunch.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#62

Post by duskwuff »

mmoskal wrote: post #55
londons_explore wrote: post #41

Earlier quoted context omitted.

The clones tend to be reimplemented from scratch. It turns out a team of 10 in a few months can reimplement a small microcontroller from just the public documentation of a competitor. By being 100% compatible, customers can move across without any engineering work, and you can reuse the same toolchain. I doubt either the manufacturer or their customers will have any legal issues. On the other hand, you probably will…

TFA says this one isn't STM32 clone though. Just the peripherals are similar. Not sure about ARM license.

> Not sure about ARM license.

I wouldn't be surprised if that's legit. The Cortex-M0/M0+ core is fairly inexpensive to license and use. It's effectively a loss-leader for ARM.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#63

Post by benj111 »

dragontamer wrote: post #58
DiabloD3 wrote: post #37

I think he's doing an important analysis, but not for DIY hobbyists: knowing how cheap your SoC is only makes sense when you're finalizing a BOM for mass production, even if they're small runs. The SoC is only one component of at least a dozen required to make a working microcontroller board. If you're doing DIY hobbyist yourself, you'll want to buy pre-mounted SoCs in a known form factor (as in, it is on a tiny daug…

RP2040 has zero flash on board and is a terrible chip to use as an example. Its actually a lot more complex to boot up than other chips, and I personally consider it closer to a microprocessor than a microcontroller (its somewhere in between). STM32F0 is a cheap Cortex M0+ that has on-board flash and on-board oscillator. Other Cortex M0+ parts are similar (with the RP2040 as a massive exception). This means that the…

The linked board includes flash.

If you're going down the route of buying a board why should you worry about the complexity of putting it all together?

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#64

Post by benj111 »

duskwuff wrote: post #62
mmoskal wrote: post #55

Earlier quoted context omitted.

TFA says this one isn't STM32 clone though. Just the peripherals are similar. Not sure about ARM license.

> Not sure about ARM license. I wouldn't be surprised if that's legit. The Cortex-M0/M0+ core is fairly inexpensive to license and use. It's effectively a loss-leader for ARM.

Why would it be a loss leader?

Surely it's because 0.1c X a bajillion chips is still a lot.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#65

Post by hakfoo »

mlindner wrote: post #8

I'm not sure why people try and go for the cheapest microcontroller. These things all have unit prices in the single digit dollars or less in actual production costs. Finding a cheap microcontroller is entirely about finding a cheap reseller of whatever you're trying to get rather than finding a cheap part specifically. Only when you get to truly large volumes such that you can get volume discounts does unit price re…

I wonder if some of it is a reaction to "growing out of" the narrow AVR ecosystem. When you have a billion options, it's neat to pick something percieved better "because I can"

I have a project that uses the now-deprecated (officially sold through, but you can find an awful lot of them of questionable authenticity on Aliexpress) Teensy++.

The Teensy++ was always expensive for what you got ($24 for an AT90USB1286), but now you can get ARM and RISC-V boards with comparable or more RAM, flash, and GPIO counts, while bumping from an 8-bit 16MHz CPU to a 32-bit 100+MHz CPU, and still pay less money. I've been fiddling with the nanoCH32V305 just because, at $6 per unit, I could put aside a fair stock of boards if I decide in a few years I want to build more of the project.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#66

Post by dragontamer »

benj111 wrote: post #63
dragontamer wrote: post #58

Earlier quoted context omitted.

RP2040 has zero flash on board and is a terrible chip to use as an example. Its actually a lot more complex to boot up than other chips, and I personally consider it closer to a microprocessor than a microcontroller (its somewhere in between). STM32F0 is a cheap Cortex M0+ that has on-board flash and on-board oscillator. Other Cortex M0+ parts are similar (with the RP2040 as a massive exception). This means that the…

The linked board includes flash. If you're going down the route of buying a board why should you worry about the complexity of putting it all together?

A lot of uCs have flash on chip, that makes integration easier.

RP2040 is harder because it won't even boot until you add flash. Other chips however will boot with just Vcc and Gnd (aka + and - power applied).

That's my point. Many many chips are actually really easy to build a board around. But not RP2040.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#67

Post by dragontamer »

LoveMortuus wrote: post #18
mlindner wrote: post #8

I'm not sure why people try and go for the cheapest microcontroller. These things all have unit prices in the single digit dollars or less in actual production costs. Finding a cheap microcontroller is entirely about finding a cheap reseller of whatever you're trying to get rather than finding a cheap part specifically. Only when you get to truly large volumes such that you can get volume discounts does unit price re…

As a person who's financial weak, I always go with the cheapest option that I can find, especially if this is my entrance ticket into the specific space. Yes, the cheapest option will probably have more issues then the more expensive one. But that's actually good, because if I can't deal with them, I probably would give up with a more expensive one. And this also allows me to experience what really matters to me and…

This won't be cheap in practice.

These are 10-cents to 70-cent SMT parts. See the link from the blogpost: https://www.lcsc.com/products/Microcontroller-Units-MCUs-MPU...

This means you need a hotair rework station and soldering iron. If you want to breadboard, you'll want a set of breakout boards to place these parts.

I suggest to beginners: work with DIP instead, so that it works on your breadboard without the need of more expensive tools. I remember back when I was in college, all I could afford was a breadboard and some chips (not even a soldering iron: too expensive for my cheap self back then).

Similarly, I expect today's cheap beginners to start on DIP + breadboards, and _maybe_ get a soldering iron, eventually. SMT parts are just outside of the reach for such cheap EEs, which is fine, DIP parts (though lower performance), still exist and still have a huge variety of important projects you can do. (OpAmps, Transistors like 2N2222 and 2N7000, voltage regulators, current regulators, references, even uCs like AVR64DD28)

-----------

Spending $0.70 on parts you literally can't use is a waste of your time and money. Buying custom pcbs is like $100 for single runs. Buying breakout boards is +$3 each plus the additional tools (hot air rework) needed to work with them.

Spending $3 on a 28-DIP package (like AVR64DD28) is in fact, the cheapest way to enter this hobby. Or alternatively, find other DIP packages (maybe something else exists: I'm not very familiar with these cheaper Chinese parts), but not the parts discussed in this particular blogpost.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#68

Post by londons_explore »

benj111 wrote: post #64
duskwuff wrote: post #62

Earlier quoted context omitted.

> Not sure about ARM license. I wouldn't be surprised if that's legit. The Cortex-M0/M0+ core is fairly inexpensive to license and use. It's effectively a loss-leader for ARM.

Why would it be a loss leader? Surely it's because 0.1c X a bajillion chips is still a lot.

Because there are a lot of other tiny microcontroller ISA's, and there isn't much value in using one over another.

If they charged much at all, then people would just use another.

Re: The cheapest flash microcontroller you can buy is actually an Arm Cortex-M0+

#69

Post by brokenmachine »

dragontamer wrote: post #67
LoveMortuus wrote: post #18

Earlier quoted context omitted.

As a person who's financial weak, I always go with the cheapest option that I can find, especially if this is my entrance ticket into the specific space. Yes, the cheapest option will probably have more issues then the more expensive one. But that's actually good, because if I can't deal with them, I probably would give up with a more expensive one. And this also allows me to experience what really matters to me and…

This won't be cheap in practice. These are 10-cents to 70-cent SMT parts. See the link from the blogpost: https://www.lcsc.com/products/Microcontroller-Units-MCUs-MPU... This means you need a hotair rework station and soldering iron. If you want to breadboard, you'll want a set of breakout boards to place these parts. I suggest to beginners: work with DIP instead, so that it works on your breadboard without the need…

>Buying custom pcbs is like $100 for single runs.

You can easily get small custom PCBs for There's a really good price comparison site at https://pcbshopper.com/

5 boards - 5cm x 5cm, 2 layer, delivered for US$9.90.

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