2009/12/15 Bill Gatliff <bgat@xxxxxxxxxxxxxxx>: > Aras Vaichas wrote: >> Unfortunately the simple coulomb counting chips have the disadvantage >> that the CPU has to be running to accumulate the pulses. Of course, >> the pulses could wake the CPU from a suspend mode, but I'd rather not >> do that just to add "one" to a counter ... >> > > Could you have the coulomb-counting chip connected to a tiny > microcontroller, or even a dedicated hardware counter? Then the main > CPU wouldn't need to wake as often, it could just ask the > microcontroller over I2C, or read/reset the hardware counter. > > b.g. Yes, but in that case you might as well just purchase a coulomb counter with a built-in accumulator and an I2C/SPI/microwire interface save yourself some PCB space and cost (maybe) Google for, say, "coulomb counter i2c" and you'll get something like this: http://eu.st.com/stonline/products/literature/ds/15269.pdf as an example The only time we used a pulse-and-polarity-output coulomb counter was with an ATmega128. The CPU had to run all the time in order to maintain its RTC so we could use it to accumulate pulses as well. It wasn't a Linux project though. Aras -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
