Richard Serge

RTI Undocumented "Feature" in QG8 & Similar

Discussion created by Richard Serge on May 21, 2006
Latest reply on Jun 6, 2006 by MIKE YETSKO
I've discovered that the RTI prescaler is cleared whenever you stop the RTI (by clearing the 3 RTIS bits). All it says in the datasheet is that the RTI is disabled when RTIS = 0:0:0. I asked about this a while back in this forum and now here is the answer to my own Q, in case anyone else has a need for this tidbit.

For my application, this is a good thing.

I tested it this way: I set up a 15ms RTI, and when the RTI fired I delayed 7ms in a software loop, then cleared the RTIS bits and immediately set them back the way they were. The result was that the next RTI occurred 15ms after the RTIS clearing and not 8ms afterwards, so the prescaler must have been cleared as well.