Hello everyone. While trying to figure out something new for a clock I'm building (including firmware), I spent some time reading all chapters of Maxim's DS3231 RTC chip datasheet. So I met a useful and often forgotten register (from ds3231 datasheet):
*Control/Status Register (0Fh)* *Bit 7: Oscillator Stop Flag (OSF). * A logic 1 in this bit indicates that the oscillator either is stopped or was stopped for some period and may be used to judge the validity of the timekeeping data. This bit is set to logic 1 any time that the oscillator stops. The following are examples of conditions that can cause the OSF bit to be set: 1. The first time power is applied. 2. The voltages present on both VCC and VBAT are insufficient to support oscillation. 3. The EOSC bit is turned off in battery-backed mode. 4. External influences on the crystal (i.e., noise, leak-age, etc.). This bit remains at logic 1 until written to logic 0 Most Arduino libraries do not handle it but it can provide useful information in case there's something wrong with the i2c clock data. Not too precise but at least you have a hint to start troubleshooting from the RTC. I would reset OSF every time the user sets the time and read its status periodically. Then display something unusual if it is set. The tubes I am using have both decimal points, so they can be used to display something useful. Now that I think of it, having 4 Nixies therefore 8 decimal points, I can display binary data too! I hope I was not the only one not using this flag :) (amongst those clock builders that do not use GPS or NTP). Paolo -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CABj2VaYig0odp8KCF_G2hpE2gUBnR2kvDYo0vxXyXqjz_Uke7A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
