Ever worn out the memory on your picaxe?

[geezer88]

Not being the sharpest tool in the shed, I tend to re-program my picaxe many, many times in the course of a project. I've been using the same 18M2 for all my development, so it has been programmed hundreds of times.

Have any of you old timers (in terms of picaxe experience) ever actually worn out one? I read that the memory can handle something like 100K writes, so it seems unlikely.

tom

 

[geoff07]

You are more likely to physically wear out the download cable, assuming it is unplugged each time.

 

[manuka]

Some years back a forum stalwart rose to the challenge & wrote a automated routine to test this out. I recall that after several weeks he'd got to a few MILLION "downloads' before the memory went wonky.

 

[nbw]

I reckon my memory will go before the IC's........

 

[Haku]

I've seen on hackaday.com someone come up with a setup to test the EEPROM limits of an ATMega328, it took 47 days and over 1.2 million writes before it failed. - http://hackaday.com/2011/05/16/destroying-an-arduinos-eeprom/

I'd imagine the Picaxe chips have a similar tolerance, meaning geoff07 is right, physical connections will wear out long before the internal flash will

 

[Dippy]

Geezer, I reckon YOU will be an "old timer (in terms of picaxe experience)" before you wear out your PICAXE.


Just a few notes for the grey matter REPROM...
1. Don't confuse EEPROM with flash. They have vastly different endurance figures.
2. K series PICs have lower endurance figures compared to non K. But many quoted figures are still classed as 'preliminary'.
3. Failure figures are based on Microchips' statistical endurance tests. Statistics mean 'probability' not 'definitive'. So, "Min" usually means 'minimum at X% level of certainty (or uncertainty)'. In practice you will (probably haha) get much better figures as Microchip will err on the side of caution so that we customers are happy.

All the hobby tests done are of course ineresting and useful but, statistically, pretty meaningless. They just confirm Microchip's erring on the cautious side - good for them And we can all smile and get on with it.

Consult Microchip for proper explanations etc.

 

[geoff07]

I believe a USB plug is rated for about 1500 insertions, and a DB9 for about 150. Probably quite a bit more for the 3.5mm jack plug. Quite a contrast with the conservatively rated 100,000 programming cycles. And that doesn't allow for the cable itself, which will probably break an internal conductor near a plug quite early on, or the USB plug solder connections, which are a weak point unless they are well supported.

So, if it matters, put your effort into the mechanicals.

1.2 million downloads, at 50/day (no holidays or time off, or much time to edit the code) will take you over 65 years. By which time the kit will be well obsolete even if you aren't.

 

[geezer88]

Thanks, All, for the interesting and informative replies. I guess I don't need to worry about wearing one out.

tom

 

[srnet]

1.2 million downloads, at 50/day (no holidays or time off, or much time to edit the code) will take you over 65 years. By which time the kit will be well obsolete even if you aren't.

But as Dippy points out the rated endurance of self write flash is much less, 10,000 cycles.

So in your example that would be achived in 200 days .....

For sure the programming cable would struggle to achive that sort of endurance, but then you dont have to mechnaically cycle the cable to program, just leave it permanently connected.

 

[Dippy]

Thanks srnet - it's good to read

I think we can agree there isn't much to worry about.
Once in a blue moon, you will get a failure just like any electronic device.
I think you'll find, for EEPROM, that Microchip is one of the most reliable manufacturers of RELIABLE / DURABLE EEPROM.

Aside Notes.
For more info on EEPROM get AN1019
For an interesting, if slightly pedestrian, video go to Microchip's website.
They will BOTH give suggestions on how to improve endurance in your App. Volts , temps , write-mode etc.
And you will see why stats are important in your calcs too.

Then you can become an EEPROM Guru