Hi all,
I sometimes hear it in the ARM presentations that execution on flash memory consumes much power and execution on RAM is recommended for the low power purpose. I would like to know the reason why accessing to flash memory consumes more power than RAM. Could anyone give me an answer?
Best regards,
Yasuhiko Koumoto.
Yes that's right.
Even when flash can be read in a single cycle it uses more power than RAM, I'm not sure why, perhaps because the RAM is usually much smaller. Flash is cheaper and for most things you don't want to keep a big RAM powered up while the processor is asleep. The big saving is if flash can be turned off for a while, e.g. if it doesn't have to be used for clock interrupts whilst sleeping or if doing something expensive like a Fourier transform.