AVR Freaks

As a part-timer in the field, and primarily a hobbyist, I am in a very different category than those who work in the field full time.

There are perhaps 1/2 a dozen AVRs that I typically work with, and they have different clocks, pre-scalers, T/C modules, etc.

The approach that works the best for me is to spend time on the high level design, sometimes in my head, but usually scratched out on paper, of the various sections of the project and how they will interact with each other.

I have a box for the different sections, and then start filling in which box gets Timer #1, which box gets USART #2, etc.

This ties in to HW pin assignments.

At the end of the day I might well have written several test programs to test various parts of what will eventually be tied together.

So any one test program is easier to keep within my head than juggling all of the program at once.

e.g.  Write my ISR driven, ring buffered, USART input routine.

Then the same for the output.

Easily tested, easily inserted into the bigger project.

When I'm actually writing code I have a three monitor setup.

So it is easy to have my Programming IDE open, one or two (Xmega), data sheets open, the schematic, my project notes, and the test program or other prior programs that used the same timer/counter in ISR CTC mode, or whatever.

You mentioned the new micro's clock above.

When I first started with the Xmega, it had a new clock system.

I spent an afternoon with my testbed, and the data sheets, and my scope, and wrote a bunch of routines to set the clock source and the PLL.

It took a little time and reading, but when that was my only focus, and I began to understand how it worked, it was then easy to write 1/2 a dozen routines for various combinations.

Now, moving forward, its just a matter of copy & paste!

So, for me, I tackle the project in small steps, and with multiple monitors for multiple files to be open simultaneously.

I agree that although I can know everything about a sub-section of the code, I have a hard time keeping that level of information within my brain for the entire project, for the more involved ones.

I also have a Word file open for "Notes" on every project.

As I make design decisions, some of which come up after the original planning..., or figure out something that took some work, I write a few notes about it in the project's Notes document.

When I come back to a project months, or even years later, it is incredibly helpful to read my prior notes, and not have to re-live the learning curves.

JC

Edit: Typo

I think ... I do a lot of "complexity reduction by abstraction" - I figure out how to do "the usual" things that I need (which tends not to be that complicated, in the end), and then ignore the other complex options until a time comes up where I need something more.

It's one of the things I like about Arduino (though their subset is REALLY minimal), and really disliked about ASF (and most of the other vendors' similar tools): I don't want to know all about the DFLL, FDPLL, and other clock options scattered across PM, SYSCTRL, GCLK, and Clock System sections of the manual.  I just want to (maybe) stick a crystal on there and run everything at the max possible speed...

(Compare the ASF "config_clocks.h" file with "What I want", which is something like "clock_init(crystal=4e6, f_cpu=48e6);")

The complexity trap is what drove people to invent Object Oriented programming languages.  I call it modular programming.  I'm not even sure what "Object Oriented" means.  All I know is C++ with it's classes (modules) is much better than C.  Stroustrup calls it divide and conquer.
 

Start is fine if you just want to run a ready-made example for a specific dev board.

If it is a different chip or a different board you get lost in the mire.

I had no problem with the legacy App Notes from Atmel.    I could port the code to a different AVR.   I could port the code to a different Compiler.

Yes,  if you can understand how to use Start it will be good experience for you.    It will enable you to use Start for your own projects.

Start makes my head hurt.   I suppose I should "try harder" but suspect that this will only make it hurt more.

Arduino limits you to (a fairly wide range of) supported boards.   It is likely that you own the hardware already.   There is proven code.   It is easier to follow.

David.

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I reckon you are doing very well for 78.  I am much younger than you.  I am already losing the plot.

I agree with Cliff.   FatFS just needs SPI.   Replace the 328P primitives with 4809 primitives for spi_init() and spi()

Power consumption just depends on going to sleep whenever you can.   Same as 328P.

The 4809 has been on the market for about 2 years.    FatFS and sleep have been done already.

Admittedly,  the Arduino 4809 boards are still going through teething stage.    The Core is stable.   Not all third party libraries support 4809 yet.

David.

I'm almost half your age, but there is one cliche that I've learnt that has been all true so far: You don't regret what you did, only those things you didn't do.

With regard to health I believe that to keep your health as much as possible you need to exercise. That goes for mentally as well as bodily. One way to exercise your head is to learn new things and figure out problems. If you stop using your brain it will deteriorate.

To me it sounds that you are reluctant to take on a new project because you fear you might not finish it. You're going to stop doing what you like because it MIGHT be a dead end? How will that get you anywhere but turning into a grumpy old man withering away in a chair complaining about all the great ideas you never got to do? With that way of thinking it would not surprise me if your mind was not able to work on these products in three years time. But if you continue to learn new things, figure out problems, exercise your brain, who knows how long you will keep it up?

Now, I understand that there might be other tings that you would like to spend your time on, like family and friends. But then we're down to priority. What do you most want to do? Can your wants be combined? Or can you share your time between the wants?

And what if you're not able to finish your product? What then? Will it have been all for nothing? I don't know. What I do know is that you will have spent your time doing something you like to do. And maybe somebody will pick it up and finish it, hopefully praising your initial effort that made it possible for him/her to make this wonderful product that might make the world a better place for who-knows how many people. That will for sure not happen if you stop doing what you like to do.

Jim, from one freak to another, stop worrying. Prioritize your wants, and start doing what you like to do. :-)

I think this should be pretty obvious even for a younger person, it just takes a little thinking to figure out why. If your average life expectancy is, say, 80 years, then when you are 30, a year means you spent 1/50 of your remaining life. But when you are 70, it represents 1/10. So a year for a 70 year old person is as valuable as 5 years for someone who is 30.

Just get yourself an inexpensive mega4809 curiosity nano board. Blink an led. Then move forward to whatever is next. Eventually the datasheet will become familiar, and you will be left with mostly just translating hardware code you currently have. Unlike the 32bit world, there is really nothing overwhelming about the avr0/1. Anyone currently using the original avr should have no trouble making the transition. Any knowledge gained will apply to the whole avr0/1 series, which has a nice range of parts. Maybe in the end it doesn't make sense to switch from what you have, but I don't think it would take a big investment of time to figure out one way or the other once you have an actual part to work with.

You also do not have to depend on any code generators like 'start' if you do not want to. There is nothing complicated going on in these mcu's. The clock is easy- you always get a valid clock at reset (one of two values set by fuse), and from there just set a prescale value as wanted, if wanted- its like two lines of code because of register protection, hardly complicated. The biggest change would probably be the pinmux, but that is not difficult either.

It seems a major concern is the system power requirements, and the ability to compare that to the current hardware version.

That begs the question, of the present version of the project, (micro, sensors, and the SD card, etc.), what % of battery capacity is spent on the micro, vs all of the other stuff?

I would think that you have a good idea as to what modules / subsystems within the micro will be used for the updated version of the project.

(Ignoring any project / software improvements by using new capabilities, (DMA, Event System, Programmable logic, etc.).)

SPI for SD, I2C for accelerometers, PB switches, setup config LEDs, etc.

So a simple test program that exercises all of the expected modules, albeit doing nothing meaningful, gives you an upper bound on the expected current consumption by the micro.

Having a measured upper bound might make you feel more comfortable, (set your mind at ease), as you move forward with the project.

JC   

Why do engineers believe they need device flexibility as much as possible so there are no fewer than 1000 datasheet pages? Of course, sophisticated high-level languages, library collections, abstraction layers ​​and different tool environments try to make this chip complexity manageable. But in my opinion, often only one complexity is exchanged for a new, possibly much larger one. Would not it be much better to keep the chips easier manageable, limit possibilities to really needed things? Perhaps to make even smarter so that not so much has to be set by hand?

But I admit I do get excited about the 8-pin ATtiny402 ($0.42) that has 4 kB flash, 256 B ram, and you can power-off and wake up when it sees its  address on I2C bus.

How true! Also, what happens with all these smart devices when the interwebs is not working?

The smart lamps in my house generally get switched on/off at the light switch. The novelty wore off pretty quick.

Some of my lights don't have switches.  But my X-10 controllers control them just fine, even when the space aliens have eaten my satellite internet connection (again).  None of it's voice-controlled, granted, and pushing buttons on the control boxes counts, I guess, as a 'light switch'. 

And no, I can't control any of them from my phone, and maybe I'm being a Luddite here, but I don't want to...  S.

'Alexa! Not that chicken timer, the other chicken timer!'.

Maybe the AI will get to a point where Alexa will hurl back some abuse like "STFU I heard you the first time" or "get off yo ass and you turn on the chicken timer".