[sdiy] Retaining button state after power off?

[rsdio at sounds.wa.com]

On Jan 31, 2014, at 23:37, cheater00 . wrote:
> Hmm, are there any recommendable arm-based chips with fram?


Strangely enough, no. Texas Instruments makes ARM chips, and they  
make FRAM, but they have not yet combined the two. If you search,  
you'll find that TI customers are already asking for the combo on  
their E2E (Engineer-to-Engineer) Forum, but the answer was not positive.

MSP430 is pretty much the only choice. They're very easy to program -  
no need to look for ARM.


As for answers to the OP's question, my personal favorite is David G.  
Dixon's suggestion to use low-power CMOS and a small battery. This  
just feels like old-school analog synth circuitry. Add a few  
strategic diodes to make sure the battery doesn't power anything but  
the chips that hold the option state, and you're good.

Brian Willoughby
Sound Consulting


>> On Jan 31, 2014, at 11:51 AM, Justin Owen <juzowen at gmail.com> wrote:
>>
>> Hello,
>>
>> I have a couple of simple analog circuits that allow you to cycle  
>> through 2, 3 or 4 options/outputs/etc using a momentary push switch.
>>
>> So, for a 2-cycle switch, click 1 is 1, click 2 is 2, click 3  
>> returns back to 1 and so on. For a 4-cycle it's 1,2,3,4,1,2,3,etc.
>>
>> The circuits output either a high or low state
>>
>> The problem is that these circuits return to their default state  
>> on power off.
>>
>> What would be the simplest way to write the button state to some  
>> sort of non-volatile storage that could be reinstated at start-up?
>>
>> I'm guessing a micro is going to be the most likely answer - but  
>> if there is a non-programming option available it would be great  
>> to hear. Failing that - absolute simplest solutions where possible  
>> please!
>>
>> Thanks,
>>
>> - J