Re: Q:Help with Microcontroller selction

On Jan 19, 6:07 am, Andreas Schweiger <andreas.schwei...@xxxxxxxx>
wrote:
Hi,>> - Battery bufferd SRAM on board (16k and more)

Easier if you can settle for 8K

There are some high end AVR that will work for you, with 8K SRAM and
2K EEPROM.


The application will have to store data which can get more and more in
time (musical allpiance).
So 8k is the adsolut minimum.

I looked at ATMELS ATmega128 but no bufferd SRAM and RTC.

Sure there is, at least for some AVRs. You can run it in power saving
mode with the RTC clock running. You should copy critical SRAM data
into EEPROM anyway. Battery SRAMs are for lazy designers.

Well, I need the SRAM for storing application data and that data can
grow by input of the user.
Storage (SD or other cards) I dont have so I need to hold the data in
battery buffered SRAM since I have a power supply which can (of course)
be switched off.
Thats why I use byttery back up.

Unless you have a big battery, SRAM will kill it quickly. EEPROM can
store data indefinitely. Any uC running SRAM will need a few mA at
least. AVR, for example, can wait for RTC interrupt with less than
100uA, if you design it right. External EEPROM or FLASH is available
as well.


Thanks,

Andreas

.

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