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

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

#31

Post by imtringued »

mlindner wrote: post #27
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…

Sure but does your financial situation change if you pay 10¢ for your microprocessor versus paying $5 for your microprocessor?

One of those can be spun into a product, the other one can't.

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

#32

Post by imtringued »

leoedin wrote: post #22
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…

Even if you're not a hobbyist, development costs will dwarf BOM costs until volumes are in the 10s of thousands - saving even a dollar per item isn't worth it if you add a few months of development time due to obscure tooling or silicon bugs.

Saving a dollar per chip(what is an item?) is going to add up to 10s of dollars per unit. I am confused.

I get what you mean regarding development costs. The cost of putting a bunch of popular/well supported components on a custom PCB is way too high. Just like the market for glue languages like python is big in the software industry I think the market for glue design tools is big in the electrical engineering industry.

If you can cut the cost of development down by 50%, the number of projects that are worth doing goes up by more than 100%. Each individual project might be less important than the next but since the cost is low it is worth it.

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

#33

Post by JKCalhoun »

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…

It's not even the price that's an issue for me, it's the breadth of the ecosystem. Something like the Teensy (just as an example) leverages the entire Arduino ecosystem from IDE to libraries — never mind community support in terms of forums, blogs, etc.

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

#35

Post by 5e92cb50239222b »

mlindner wrote: post #27
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…

Sure but does your financial situation change if you pay 10¢ for your microprocessor versus paying $5 for your microprocessor?

Well.. yes? A relative of mine is a student and is into electronics. His monthly income (with various bonuses for good academic performance) is around $100 per month IIRC. $5 is a significant sum for someone like that.

Especially when developing something. I let out magic smoke from many a chip over the years (or partially destroyed one of the internal components, rendering the whole chip pretty much useless).

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

#36

Post by detrites »

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…

A few potential reasons:

I could imagine working in the industry professionally, it might become just as second nature to bean-count parts cost as say, to optimise compiled code size as a result of typically constrained memory environments.

Hobbyists who don't work in the industry, may yet aspire to in the future. So, would therefore be wise to develop that ethos, or - who knows - maybe that hobby project could later become something produced in high volumes?

Why needlessly limit a design, when designing something from scratch? It's rewarding to go for optimum goals. It'd be rewarding to aim to design an "optimum cost" system just as it would be for any other optimums one might target.

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

#37

Post by DiabloD3 »

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 daughter board, and that board has a known pin-out that remains consistent across clones). Example: the Pro Micro.

A Raspberry Pi branded Cortex-M0+ on a Pro Micro clone board sold under the Sparkfun brand is $11: https://www.sparkfun.com/products/18288 All the components to have a fully working microcontroller out of the box is included; the SoC, RAM, flash, USB connector, the rest, and it's all machine placed and soldered, and individually tested.

The dev board of the SoC he selected is $5, but get shipped from China and seem to be incomplete dev kits (no USB, no flash reprogramming pins, and the docs aren't great); it also doesn't seem to be a standard/popular form factor.

The analysis in the article is only the part that would lead you to "if I wanted to make my own Pro Micro-sized microcontroller, which SoC is cheap but good"; you still need the cheap but good equivalents for the rest of the components and then actually be able to solder it (SMD components suck for humans to hand place).

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

#38

Post by DiabloD3 »

TheLoafOfBread wrote: post #21
kken wrote: post #11

Earlier quoted context omitted.

I think the main appeal is to work with small devices that have well defined resources. Just consider the popularity of the ATtiny85. However, low end 32bit devices are also available from reputed suppliers. In fact, STM just announced the STM32C* series which is also aimed at replacing 8 bit controllers. The cost benefit may only be true for low numbers and when sourcing from distributors. I am fairly certain that t…

Can I buy STM32 in some decent numbers, or are they still made out of unobtanium?

This is the problem when building around a specific part, no matter how cheap. The hobbyist community has selected certain daughter boards to clone, and then place SoCs on them that can run Linux (or any other hobbyist OS). If one SoC vanishes from the market, you can drop another one in, and often with zero changes to your design, keep going.

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

#39

Post by Roark66 »

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…

One of big problems today is availability. Even if other microcontrollers do cost single dollars (which isn't often a case, some for example stm32 chips that were cheap are now going for $40 they're so rare). If you're paying $0.1 per unit you can buy a hundred (or more) for a lifetime supply if they meet your requirements.

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

#40

Post by londons_explore »

fzliu wrote: post #7

> The PY32F030 parts advertise a typical low-power stop mode current consumption of 4.5 µA when using a 1.0V setting with the internal regulator, and I was able to get the part to drop down to 5 µA in my testing. Meanwhile, the STM32F030 uses less than half of that in stop mode I've had the same experience with cheap (Chinese) microcontrollers - power consumption is usually higher across all modes.

It's due to leakage current due to the design being produced on a less refined silicon process.

Live with it, or have external circuitry to power down the whole chip when not in use.

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