Posted on November 23, 2007 at 08:23Salvatore,
your task is either simple and somewhat complicated.
If you do not bother power consumption, you can use a timebase counter that overflows every ms or two.
Some ST7, I mean ST7FLITE3x family, can even cascade the timebase counter with the auto-reload timer to measure long time periods.
From the overflow interrupt handler you can acquire the analog input and store it into the eeprom.
This simple algorithm can be improved:
- acquire more samples and average the samples to reduce noise.
- stop the micro between the ADC conversions to reduce power consumption.
The former is an easy task when you take 256 samples (to divide by 256 all you need is to discard the lower byte), whilst the latter one needs the Auto-Wakeup Timer to be calibrated and programmed.
Please, keep in mind that, while you are writing a byte to EEPROM (it may take some ms), the counter can overflow, so you must pay attention to what you do in the interrupt handler.
Ciao
EtaPhi
