If you really really need a low power device

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papaof2

Senior Member
You never know what may turn up on slickdeals.com - this week included a microprocessor experimenter's kit for $4.30US, so I followed the link to see what the chip specs were.

The 16 bit TI MSP430 series power requirements:

0.1-µA RAM retention
0.8-µA real-time clock mode
250-µA/MIPS active

Considering some recent posts, having a built-in RTC would make things much easier for first-time RTC users. Maybe this can be a new target for MicroChip ;-)

The experimenter board from TI is $4.30US (includes two chips & free shipping) but it is backordered until some time in August. The development IDE is a free download, but I think it's in C.

I haven't used C in probably 5 years; for me, that would almost be starting on the ground floor again.

Think I'll stick with PICAXE and use the next larger battery size (AA instead of AAA) in my projects.

As the title says "If you really really need low power"...

John
 
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westaust55

Moderator
papaof2 said:
. . .
Think I'll stick with PICAXE and use the next larger battery size (AA instead of AAA) in my projects.

As the title says "If you really really need low power"...

John
Click to expand...
And there is still scope to work your way up through “C” cells, “D” cells and into the big league :)
 
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Dippy

Moderator
Well, I don't need to remind anyone that there are many uP manufacturers out there.
And there are many devices that , in certain aspects, are far better than Microchip's.
And i don't need to remind anyone that if you wish to create a wide range of products using different micros then you will have to learn C - this is the common link between all of them. Forget in depth learning of C++++++, just the basic C.
Yes, certain differences, that is obvious, but C is a must if you want to get on with all of them - and be able to pinch sample code too :)
(Now, where's my book?)
 
J

John West

Senior Member
I'd buy a golf cart battery to run my PICAXE before I'd buy a book on C programming. They're only $90 US. How much is my time worth? I already know a smattering of PLM, PASCAL and a multitude of BASICs, the learning of which have already robbed me of many months of my live. That should be enough. Life's too short to torture myself learning more programming languages.

It's not that old dogs aren't smart enough to learn new tricks, rather they're smart enough not to bother learning unnecessary new tricks.
 
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Dippy

Moderator
If I wanted an RF module with processor half the size of my thumbnail then I'm afraid it's C-time.
If I want it in a shoebox then I'll use John's method :).
The old Horses for Courses again isn't it.

It's people's choices so fair enough. And I know what you mean... it's called exhaustion, usually age-related.
However, the 'torture' of learning C means you have the skill-basics to be able to programme most different types of micro.
A knowledge of BASIC only will allow just a few. Albeit they are good ones but there are certain 'speciality' micros which will be closed off to you unless you have a basic grasp of C.

I think C is horrible and I know of two BASIC compilers, that for a lot of common stuff, will (alledgedly) produce better code for 18F PICs.
 
hippy

hippy

Ex-Staff (retired)
papaof2 said:
0.1-µA RAM retention
0.8-µA real-time clock mode
250-µA/MIPS active
Click to expand...
The 100nA RAM retention is effectively the lowest power one can operate at without loosing memory data, so in practice minimum draw would be that plus whatever is consumed in its sleep mode. The latest Microchip devices claim 65nA sleep modes including data retention.

At 250uA/MIP that seems comparable with the latest PICmicro devices.

I think one has to always take headline figures with a pinch of salt substitute. I'm still trying to work out, when I eat a whole food item labelled "serves four", if that means I've got an unusually veracious appetite or the manufacturer has over stated their claim :)

papaof2 said:
Considering some recent posts, having a built-in RTC would make things much easier for first-time RTC users. Maybe this can be a new target for MicroChip ;-)
Click to expand...
I don't expect that will happen as the PICmicro has everything which allows a 32kHz watch crystal to be connected and an RTC to be created in software already. I've done that for a number of PICAXE including the 08M but the practice doesn't seem to have caught on.

The advantage of a separate chip RTC solution is usually that one doesn't have to worry about low power modes; just power the controller on or off, and leave the RTC with a battery backup to sort itself out.
 
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papaof2

Senior Member
Sometimes the choice to learn/relearn a language is simply based on value returned for effort expended.

In the days of the Radio Shack Color Computer (CoCo), I had a C compilier (running from two 360K floppy disks). I learned enough 6809 assembly to be able to correct some errors in the compiler's library. On the other hand, my real world job was managing and programming UNIX computers - with most of the programming done in C. In the years since then, I have used a variety of languages: Basic-09 for OS-9, Turbo Basic and Power Basic for DOS, Visual Basic (several versions) for Windows, various database products from dBASE (DOS/UNIX) to SQL Server to MySQL, html & ASP, some C++, even a little java.

Most of my projects are personal or for family/friends and (other than lunch) there's no income. If the need arises for something like TI's 16 bit MSP430 series, I'll bite the bullet and pull the C books off the shelves ;-) Meanwhile, I'll likely take the easiest road to a workable product.

Horses for courses? Exactly! Race horse on the track, pony for the kids to ride, plow horse in the field, Clydesdale pulling a heavy wagon.

John
 
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papaof2

Senior Member
And you knew how to boot a PDP-11 via the front panel keys?

<long ramble>
After spending more than 6 hours yesterday with a chainsaw - clearing limbs downed by a freak storm ("straight-line winds" between 60 & 70MPH) - I'm not sure if I could get down to the switch panel and get back up again.

Fortunately for us, all the damage was to landscaping (several large limbs from a poplar tree sailed 40 feet to land in a flower bed). The tree service company was here in the early afternoon today to remove the 5 limbs that were broken and dangling, two hanging over the edge of the house. I'm confortable using a chainsaw at ground level, but I let the professionals climb the trees. One neighbor lost 3 large trees, one (possbly 80 feet tall) spanned his lot from property line to property line and crushed the roof and back window of a car in the driveway - but no injuries. The power lines in the subdivision are underground, but the electric substation that powers our area is feed via overhead lines (as are the other 6 or 8 substations that were affected - all in a line on the map) and the substations often feed the subdivisions via overhead lines to the point of going underground. We were part of the 10,000+ homes without power from Friday evening to Saturday morning/afternoon (16 hours for us). I have a small generator (big enough for the central heat and fridge) and started it to keep the fridge cool about the time I started the chainsaw: 8:30AM Saturday (the neighbors who might have been disturbed by the noise were already out lookng at the damage). In the 5+ years we've been here, the longest previous electrical outage was less than 2 hours - not worth the effort to crank the generator.

Not exactly how I planned to spend Saturday - and I would much rather have spent at least part of the money on techie toys instead of tree work...
</end long ramble>

John
 
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