Senior Member
Joined: 17/11/2011
Location: AustraliaPosts: 231
| Posted: 06:11pm 25 Dec 2011 |
the RTCC can provide an error of less than 0.66 seconds per month.
1. But what Microchip neglects to tell you is that the calibration is at a fixed temperature (ambient) and any deviation from this temperature curve will create greater time errors. That is where a TCXO - Temperature controlled oscillator works better. What is really needs to be done is to add a small UEXT dongle using the 8 pin DS3231m with coin cell battery holder. Add this to the internal UEXT connector.
2. It takes some very expensive calibration test equipment to do this calibration. It should have already been done at the factory eg Olimex. This means every DM board should have a unique set of calibration curves to match the watch crystal?
and run it to pin7 (D10) on the DuinoMite
3. I think that is a shared pin number? ... using pins 1 or 2 (with a pullup) would be a better choice.