Author Topic: What µC are you preffering  (Read 30883 times)

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Offline NorthGuy

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Re: What µC are you preffering
« Reply #125 on: April 21, 2020, 12:58:55 pm »
Yes indeed. There is no reason for family sedan, "car of the year" to be the coice of transportation for everything. Yet when random & clueless people are seeking for means of transportation you usually suggest them what? - Car of the year.

When something gets popular, people feed from each other to augment popularity, sometimes way beyond reason. Therefore popularity is very poor as a guide to engineering.

There's an excellent book. It's slightly on a different subject, but it explains the phenomenon very well:

Charles MacKey: "Extraordinary popular delusions and the madness of crowds".

This is a very interesting read.
 

Offline ogden

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Re: What µC are you preffering
« Reply #126 on: April 22, 2020, 06:31:30 pm »
When something gets popular, people feed from each other to augment popularity, sometimes way beyond reason.
Does not apply here. MCU is not consumer product. Those who buy MCU in significant volume usually are successful companies. Saying that they feed from each other to augment popularity is beyond reason.
 

Offline Sal Ammoniac

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Re: What µC are you preffering
« Reply #127 on: April 22, 2020, 09:04:23 pm »
When something gets popular, people feed from each other to augment popularity, sometimes way beyond reason.
Does not apply here. MCU is not consumer product. Those who buy MCU in significant volume usually are successful companies. Saying that they feed from each other to augment popularity is beyond reason.

+1

When companies I've worked for evaluated MCUs for use in products, we never considered what competitors were using in their similar products. We evaluated each MCU for fitness for our purpose and not on its popularity.
Complexity is the number-one enemy of high-quality code.
 

Offline splin

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Re: What µC are you preffering
« Reply #128 on: April 22, 2020, 11:53:06 pm »
we never considered what competitors were using in their similar products.

Then perhaps you should - maybe your competitors know something you don't? ([EDIT: I'm not referring to 'you' specifically - what you did worked presumably worked well for you/your company - but I don't think your approach is desirable for many/most developments].

'Considering' doesn't mean 'blindly following' or even conducting a protracted in depth analysis. But if your competitors are reasonably competent you should at least consider, even if briefly, why they might have made their choices the way they did.

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We evaluated each MCU for fitness for our purpose and not on its popularity.

Risking choosing a product which could get very expensive or obsoleted in short order because you are the only manufacturer in the market not using the popular part - which gets ever cheaper as popularity drives volumes and even brings in second or third sources? Ok. the latter isn't very common these days but does still happen occasionally - eg. the GD STM32 clones.

Popularity is good and should be high on the list of factors influencing the decisions. Popularity likely means a larger pool of available experienced developers in the job market. Third party tools, software and hardware may become available for popular parts, but not obscure ones. This might become important later when you find that the part itself, or the maufacturer's tools turn out to have some crippling bugs, limitations or performance and productivity stifling issues that they are unwilling to fix because of low demand.

Popular parts are much more likely to get silicon revisions to fix errata and/or improve cost and performance and to add new features. At the least the manufacturer isn't going to put much effort into support for low volume parts.

Meanwhile your competitors are laughing all the way to the customers, even if their design isn't the most elegant or 'optimal' from an engineering viewpoint.

[EDIT] Clearly this is all very dependent on the market you are operating in - highly specialised, low volume markets developing one off solutions for specific customer requirments is very different to consumer type products where the design might have a long lifespan with incremental development and improvement over many years.
« Last Edit: April 23, 2020, 12:29:19 am by splin »
 

Offline NorthGuy

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Re: What µC are you preffering
« Reply #129 on: April 23, 2020, 03:46:58 am »
Does not apply here. MCU is not consumer product. Those who buy MCU in significant volume usually are successful companies. Saying that they feed from each other to augment popularity is beyond reason.

May be they do, but for every big and successful company, there are thousands of small guys who recommend MCUs to "random and clueless" people because this is an "MCU of the year" - marketers, journalists, bloggers and whatnot. That's what creates popularity for MCUs. Big companies whose decisions don't get published anywhere has very little to do with popularity.
 

Online SiliconWizard

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Re: What µC are you preffering
« Reply #130 on: April 23, 2020, 05:44:02 pm »
Popularity certainly does influence to some degree vendors/architectures choice in big companies, especially since the selection process is often only partially in the hands of tech people. And just like with hiring people, using "popular" solutions just makes things easier for the deciders that are definitely not the ones who design products. If you're going for ARM, what's the probability you could get in trouble with your choice? Now if you're going for some obscure architecture/vendor for your next big project, however a great fit it was, and the project fails (for any reason), your choices are likely to be held against you (even if that's not relevant.)

In the same vein, some of you may "never" consider what competitors use, but I've seen this pretty frequently myself. When a prestigious company uses something specific and it's known in the field, it certainly does influence decisions for others in some way.
 

Offline NorthGuy

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Re: What µC are you preffering
« Reply #131 on: April 23, 2020, 06:40:26 pm »
... if you're going for some obscure architecture/vendor for your next big project, however a great fit it was, and the project fails (for any reason), your choices are likely to be held against you (even if that's not relevant.)

Of course, if you chose something and then, two years from now, when your product is in full bloom, the vendor stops selling the chip or increases price 5 times, you're doomed. There's no way you can prevent this 100%. All vendors want to sell something hot and popular, but very few are willing to continue with products which lost popularity (as all the products eventually do). The only indication is the past behaviour of the vendor. Something you should consider.

These are rational considerations. Popularity, however, is irrational - you chose something not because you have your own considerations, but because you rely on others. This also absolve you from responsibility - you have chosen something that other people praised so high, how can you be responsible for them? So, many people use what other recommends, and then start recommending the same to others, thus magnifying popularity. This is very common for bureaucrats at all levels and regular folks alike.
 

Offline Sal Ammoniac

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Re: What µC are you preffering
« Reply #132 on: May 19, 2020, 10:46:06 pm »
We evaluated each MCU for fitness for our purpose and not on its popularity.
Popularity is good and should be high on the list of factors influencing the decisions. Popularity likely means a larger pool of available experienced developers in the job market. Third party tools, software and hardware may become available for popular parts, but not obscure ones. This might become important later when you find that the part itself, or the maufacturer's tools turn out to have some crippling bugs, limitations or performance and productivity stifling issues that they are unwilling to fix because of low demand.

Did you read what I wrote? I said we evaluated for fitness for our purpose. So what if a part is popular? It can be the most popular part in the world, but if it doesn't fit our application, it's useless to us. I've seen too many engineers try to shoehorn an application onto an MCU that wasn't suited for that application merely because the part was popular and was the latest craze in the industry.
Complexity is the number-one enemy of high-quality code.
 

Online SiliconWizard

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Re: What µC are you preffering
« Reply #133 on: May 19, 2020, 11:02:16 pm »
We evaluated each MCU for fitness for our purpose and not on its popularity.
Popularity is good and should be high on the list of factors influencing the decisions. Popularity likely means a larger pool of available experienced developers in the job market. Third party tools, software and hardware may become available for popular parts, but not obscure ones. This might become important later when you find that the part itself, or the maufacturer's tools turn out to have some crippling bugs, limitations or performance and productivity stifling issues that they are unwilling to fix because of low demand.

Did you read what I wrote? I said we evaluated for fitness for our purpose. So what if a part is popular? It can be the most popular part in the world, but if it doesn't fit our application, it's useless to us. I've seen too many engineers try to shoehorn an application onto an MCU that wasn't suited for that application merely because the part was popular and was the latest craze in the industry.

Yes, that's hype-driven development. ;D
 

Offline splin

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Re: What µC are you preffering
« Reply #134 on: May 21, 2020, 10:55:21 pm »
Did you read what I wrote? I said we evaluated for fitness for our purpose.

Of course I did thank you - that was why I responded.

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So what if a part is popular?

Perhaps you could have had the courtesy to have actually read what I wrote? It was all about why popular is important.

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It can be the most popular part in the world, but if it doesn't. fit our application, it's useles to us.

Obviously, that goes without saying. Why would anyone choose a part that wasn't fit for purpose? I didn't say you should select a part because it is popular - what I actually said was:

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Popularity is good and should be high on the list of factors influencing the decisions.

Engineering is about trading off a multitude of factors including performance, price, ease of development, reliability and availability amongst many others. 'Popularity' has an impact on many of those in both the short and long terms. Your ideal 'fit for purpose' choice won't be fit for any purpose if you can't buy them because they proved to be so unpopular that the manufacturer stops making it.

Or they were unpopular because they are bug-ridden carp that don't work in the specific configuration that you need to use because the chip developers didn't test it in that mode and nobody else ran across it due to its unpopularity. And when discovered the manufacturers won't fix it because - you guessed it - it's unpopular.

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I've seen too many engineers try to shoehorn an application onto an MCU that wasn't suited for that application merely because the part was popular and was the latest craze in the industry.

I'm sure that happens though I've never encountered it personally (at least in hardware design - software is a very different matter!). There are inexperienced/misguided/incompetent engineers everywhere but in a well run organisation good processes and procedures, including design reviews, ought to reduce the number of such poor design choices getting past first base.
 

Offline m12lrpv

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Re: What µC are you preffering
« Reply #135 on: May 21, 2020, 11:16:42 pm »
Stepping into the room a bit late but i'm interested in the topic. (not the argy bargy)

Like many hobbyists I started with arduino but imediately stepped away from blinking led's and started doing stuff with the chips themselves directly. Logically I moved into tiny's as there's no sense using an atmega when you only need 3 pins doing something.

Wanting to expand my horizons I tried the TI MSP430 and TM4?125 Arm chips. The issue there was they were a nightmare to program and while I did do some interesting things with the TM4 it was just too inefficient time and effor wise to try and use them.

A few years on now and I've just started shipping out another project with the atmega328p at it's heart and every pin was utilised. No room to add features in the future.

But what for the future?

I'm seeing STM32 everywhere but is that a viable upgrade?

What about programing environments? Ti's CCS really burn't me badly but from the chatter i'm seeing it sounds like things are better in STM land. I don't get a hard on from reading datasheets, they're a means to an end, so something like CubeMX sounds useful for those just trying to get a job done like I am.

The problem I have is that my projects are typically analog and the ADC is a big part of it.

I've played with analog on 3.3v before (The Ti chip) and the noise just swamps out the detail. I've spent a lot of time getting the atmega ADC's to work with good precision and I can't afford to lose that.

What are some good uC options for analog work where the inbuilt ADC's aren't complete crap? (Yes I saw Blueskull recommending PSoC 5LP and damn they look nice but oh the cost)
 

Online wraper

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Re: What µC are you preffering
« Reply #136 on: May 21, 2020, 11:29:45 pm »
What are some good uC options for analog work where the inbuilt ADC's aren't complete crap?
Define what's "aren't complete crap".
 

Offline m12lrpv

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Re: What µC are you preffering
« Reply #137 on: May 21, 2020, 11:39:05 pm »
What are some good uC options for analog work where the inbuilt ADC's aren't complete crap?
Define what's "aren't complete crap".
Actually I won't because I don't want to restrict people responses. Needless to say though something that can handle more than just an analog keypad matrix.
 

Online wraper

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Re: What µC are you preffering
« Reply #138 on: May 21, 2020, 11:58:18 pm »
Actually I won't because I don't want to restrict people responses. Needless to say though something that can handle more than just an analog keypad matrix.
Vague as hell. Thus you will not get any suggestion at least for me. Don't want to waste time listing something that probably will be "crap" in your opinion. Or something that's higher spec than needed and thus too expensive.
 

Offline m12lrpv

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Re: What µC are you preffering
« Reply #139 on: May 22, 2020, 12:05:57 am »
Actually I won't because I don't want to restrict people responses. Needless to say though something that can handle more than just an analog keypad matrix.
Vague as hell. Thus you will not get any suggestion at least for me. Don't want to waste time listing something that probably will be "crap" in your opinion. Or something that's higher spec than needed and thus too expensive.
You could have just not posted at all and saved everyone from your attitude.

You're stating that you won't post any suggestions because you're expecting me to come back and declare it to be crap in my opinion. Suggesting I will do that is highly offensive. I'm after opinions based on experience and it would be very wrong for me to ask such a thing and then criticise any genuine responses. That's not how I work and you should either apologise or delete your posts.
 

Online wraper

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Re: What µC are you preffering
« Reply #140 on: May 22, 2020, 12:08:53 am »
Sorry for refusing giving answer to completely undefined question.
Quote
because you're expecting me to come back and declare it to be crap in my opinion.
Don't put words in my mouth. You may not say it, and keep such opinion to yourself. Regardless if you say or don't say anything, it becomes waste of time posting answer of no use.
« Last Edit: May 22, 2020, 12:13:02 am by wraper »
 

Offline m12lrpv

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Re: What µC are you preffering
« Reply #141 on: May 22, 2020, 12:13:13 am »
Sorry for refusing giving answer to completely undefined question.
No probs.  :-+ But you do understand that this isn't stack overflow?
« Last Edit: May 22, 2020, 12:16:02 am by m12lrpv »
 

Offline brucehoult

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Re: What µC are you preffering
« Reply #142 on: May 22, 2020, 12:20:15 am »
The problem I have is that my projects are typically analog and the ADC is a big part of it.

I've played with analog on 3.3v before (The Ti chip) and the noise just swamps out the detail. I've spent a lot of time getting the atmega ADC's to work with good precision and I can't afford to lose that.

What are some good uC options for analog work where the inbuilt ADC's aren't complete crap?

Seems like you must be doing pretty specialized stuff.

The ADCs in things like ATTiny and ATMega or probably anything else  are more than good enough for most things people want them for. I don't know how accurate the last bit or two is on an absolute scale but I've always found the output to be stable and monotonic. On the ATTiny85 You can do 15k samples a second using the recommended 200 kHz ADC clock (which can be pushed to 1 MHz with some loss of accuracy?)

That's more than good enough for old fashioned telephone audio.

If you want to do CD quality then of course you need much better. I guess probably there are MCUs with built-in ADCs that good, but it might be easier (and for the analogue design too) to use an external ADC.
 

Online PCB.Wiz

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Re: What µC are you preffering
« Reply #143 on: May 22, 2020, 12:34:30 am »
The problem I have is that my projects are typically analog and the ADC is a big part of it.

I've played with analog on 3.3v before (The Ti chip) and the noise just swamps out the detail. I've spent a lot of time getting the atmega ADC's to work with good precision and I can't afford to lose that.

What are some good uC options for analog work where the inbuilt ADC's aren't complete crap? (Yes I saw Blueskull recommending PSoC 5LP and damn they look nice but oh the cost)

SiLabs EFM8LB1 spec a 14b ADC, and 12b DACs, so that could be worth evaluating for 'better analog' smallish MCUs.

If you want to go more fringe, and more extreme Analog, a part like this configurable sensor signal conditioner caught my eye
ZSSC3240CI3https://www.idt.com/us/en/products/sensor-products/sensor-signal-conditioners-ssc-afe/zssc3240-high-end-24-bit-sensor-signal-conditioner-analog-and-digital-output?utm_campaign=sensors_ssc_zssc3240&utm_source=press_release&utm_medium=press_release&utm_content=zssc3240_product_page


that one claims
24-bit analog-to-digital converter and 26 bits digital-signal-conditioning math core
Reprogrammable, nonvolatile memory (NVM)
Programmable 16-bit digital-to-analog-converter and output

Some vendors are now doing Wide Vcc MCU with high end ADC included
https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rx/rx200/rx23e-a.html
and they also have ARM32 core versions with 24b and 16b ADC  & 12-bit D/A, 8-bit D/A
https://www.renesas.com/us/en/products/microcontrollers-microprocessors/ra/ra2/ra2a1.html#productInfo

« Last Edit: May 22, 2020, 02:54:14 am by PCB.Wiz »
 
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Offline splin

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Re: What µC are you preffering
« Reply #144 on: May 22, 2020, 12:36:29 am »
What are some good uC options for analog work where the inbuilt ADC's aren't complete crap? (Yes I saw Blueskull recommending PSoC 5LP and damn they look nice but oh the cost)

Well it is a bit of a "how long is a piece of string question", but here goes anyway (all based on datasheet values).

The LPC4370 has an 80MSPS 12 bit ADC with approx 10bits ENOB. 80MSPS lets you do quite a bit of oversampling to increase the resolution and still get decent sample rates.

The STM32F1 and STM32F4 processors 12bit ADCs but they are a bit noisy achieving around 10 bits ENOB. The F4's have up to 3 x 2.4MSPS ADCs which can be interleaved to sample a single signal at 7.2MSPS.

The STM32F3 range have up to 4 x 5MSPS 12 bit ADCs with 11.2bits ENOB. In practice someone here posted that the internal buses/DMA aren't fast enough to allow all 4 to sample at full speed, topping out at around 18MSPS total (if I remember correctly). In any case you have precious little processor speed to process 18MSPS of data if you need continuous streaming at full speed. You can average the samples for oversampling (but you have to do it in assembler) but not much else. Pairs of ADCs can be interleaved to 10MSPS.

The STM32F373 and 378 have 3 x 50KSPS 16 bit sigma-delta ADCs with over 14bits ENOBs.

The STM32H7 range are the best that I know of, on paper, with 3 x 3.6MSPS 16 bit ADCs with 13.2bits ENOB. But there are some severe limitations - for the gory detail see:

https://www.eevblog.com/forum/microcontrollers/stm32h7-adc-performance-ya-gotta-read-the-fine-print!/

Also note that oversampling can increase the resolution/noise performance it doesn't improve the linearity errors (INL) which rarely betters 12bits in an MCU - even the above '16 bit' ADCs.
 
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Offline m12lrpv

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Re: What µC are you preffering
« Reply #145 on: May 22, 2020, 12:46:07 am »
Seems like you must be doing pretty specialized stuff.
Induction sensors measuring metal thickness variations to a few microns. It's hobby stuff though. The ADC's on the atmega's can be massaged to give good stability providing the board layout is done properly. Fed a nice stable external V-Ref and controlling when and when not to sample, like when switching ADC channels, will let it perform pretty well.


 

Offline chriva

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Re: What µC are you preffering
« Reply #146 on: May 22, 2020, 12:58:20 am »
Usually I'd say what gets the job done but I'm going to change the question slightly: which one has been the most fun.

I'd highly recommend old powerpc or cpu32(embedded 68020 ish) processors with a TPU. What can be done with that thing is up to your imagination. Extremely powerful co-processor for anything timing based.
 

Offline nigelwright7557

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Re: What µC are you preffering
« Reply #147 on: May 22, 2020, 01:46:16 am »
Hi, which µC are you preffering and why?
Where to find a good reliable microcontroller, well documented, good debug features, fast to program, easy to learn good IDE, good programmer/debuger?
Or is there not the one and really depends on your needs what you prefer and which manufacturer you choose?

Choosing a microcontroller can be a nightmare especially the more complicated ones.
Its vital you read datasheet and errata sheets before choosing one.

I just started a atsame70j21b USB scope project. What a pig to even work out the power supply connections, its complicated by core running off low volts yet i/o can run off 3v3. I took ages to try to find a connection for the Snap programmer to the uC.
When  I eventually got to power it up it programmed once and the wouldnt program again. However it did flash a LED !
I opened a ticket with Microchip and they looked at my circuit.
I had reset on Snap connected to pin 6 instead of pin 1. They also threw a huge spanner in the works by telling me that the uC I had chosen the USB hardware has a bug and doesn't work !

While MPLAB x and Harmony 3 are very clever it is highly complex.
 

Offline westfw

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Re: What µC are you preffering
« Reply #148 on: May 22, 2020, 02:09:55 am »
Quote
we evaluated for fitness for our purpose.
the "problem" is that for many, many, applications, you have a large choice of chips that are "fit for the purpose", and are left with modifiers "I know someone who has used it before", "the local SE seems very knowledgeable", "The datasheet seems more readable", "the vendor has been around for a long time", "there seems to be a good upgrade path to bigger, faster, chips", "There's a good online forum", "the vendor IDE is slightly more palatable than that other IDE", "there is more than one compiler", "the architecture is popular", and etc...
 

Online PCB.Wiz

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Re: What µC are you preffering
« Reply #149 on: May 22, 2020, 02:58:42 am »
Seems like you must be doing pretty specialized stuff.
Induction sensors measuring metal thickness variations to a few microns. It's hobby stuff though. The ADC's on the atmega's can be massaged to give good stability providing the board layout is done properly. Fed a nice stable external V-Ref and controlling when and when not to sample, like when switching ADC channels, will let it perform pretty well.

For that, you could also look at the new TI LDC1001  5V, 16-bit Rp, 24-bit L resolution, inductance to digital converter
https://www.ti.com/product/LDC1001
 


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