I2C Interaction + ISR

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi All,
I'm going pretty good with my project, but seem to be kind of stuck...
One of the steps involve logging date+time (from a DS1307) and some values every a fixed interval of time.
I poll these values via a timer interrupt, BUT, as far as I have been reading, I cannot "ask" the DS1307 for date/time inside the ISR because the I2C interaction is interrupt-based, and, obviously, the interrupts are disabled when handling another Interrupt (the timer interrupt).
Has anyone ever dealt with this before? This is kind of a "show-stopper" for me...

Thanks!

2

The solution is to use the ISR to set a flag (a variable).

Then in the main loop you just look for the flag and when you see it set do what you have to and clear it.

You only have to watch out that the doing what you have to is faster than the rate the interrupts come in.