Date: Sat, 19 Feb 2022 09:22:01 +1030 From: "Daniel O'Connor" <darius@dons.net.au> To: Archimedes Gaviola <archimedes.gaviola@gmail.com> Cc: freebsd-arm@freebsd.org Subject: Re: DS3231 RTC module not detected Message-ID: <2DF482A7-FEFC-4833-A16B-A7A01B8713DD@dons.net.au> In-Reply-To: <CAJFbk7Ed2R8M2xAkJQAjiivZie=8Ca_Rt50YEG4P3yWzQLQhrg@mail.gmail.com> References: <CAJFbk7EtkjnFBJgr-L3faxaQ2saNgEQ%2BLRPWbRySpwY8wJRh=Q@mail.gmail.com> <F2EFEDCC-1E00-4221-8AF9-3744A7AC359C@dons.net.au> <CAJFbk7Ed2R8M2xAkJQAjiivZie=8Ca_Rt50YEG4P3yWzQLQhrg@mail.gmail.com>
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> On 19 Feb 2022, at 00:52, Archimedes Gaviola = <archimedes.gaviola@gmail.com> wrote: > Thanks for the info! I followed similar with your DS1307 RTC by = creating a ds3231.dtso file and then compiling it with dtc to generate a = ds3231.dtbo. The result is it is detected as MAX77620 RTC on 0xd0 = address but when I run an i2c scan, the address detected is 68. Does = this should match? Mine was detected similarly: iic0: <I2C generic I/O> on iicbus0 rtc0: <MAX77620 RTC> at addr 0xd0 on iicbus0 usbus0: 5.0Gbps Super Speed USB v3.0 rtc0: registered as a time-of-day clock, resolution 1.000000s I am not sure why it shows up like that but it does seem to work. > With this setup I could update the date and time now by initiating an = ntpdate to match our time plus invoking tzsetup command for my timezone = which is doing well without any issue. Now, the moment I shutdown the = system and plug back the power cable (with disconnected Ethernet cable = just to make sure NTP servers are not called for updates upon restart) = the time remains as it was before shutting down and then upon bootup = system clock continues. I am expecting that it should be real time even = if the RPi4 system is shutdown or detached from power due to the battery = that will sustain the continuity of the clock. I'm sure that I'm having = good DS3231 modules as I also tested my existing and another new spare = and it is tested with OpenBSD too. Below are the system info. Is there = anything I've missed? FreeBSD 13.0-RELEASE have the same outcome and = behavior. That is strange, I tested powering mine off and it kept time but I am = not 100% sure it was advancing correctly - I didn't take a precise note = of when I powered it off etc.. Unfortunately it's not physically with me so I can't test it right now. I do note this sysctl: machdep.rtc_save_period: Save system time to RTC with this period (in = seconds) Which suggests to me that the clock could be up to 30 minutes off if the = power is removed (I believe it gets flushed out on a clean shutdown = though). Perhaps that is the problem? -- Daniel O'Connor "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum
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