DS3231 RTC Board Real Time Clock Module for Arduino Raspberry Pi

Megjott a https://www.aliexpress.com/item/DS3231-RTC-Board-Real-Time-Clock-Module….

RPi 0W alatt mukodik 3.3 Volton (Rock64 kesobb lesz tesztelve):

modprobe i2c-bcm2708
modprobe i2c-dev
modprobe rtc-ds1307
echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
hwclock -D

root@raspberrypi:~# hwclock -D
hwclock from util-linux 2.29.2
Using the /dev interface to the clock.
Last drift adjustment done at 1551898398 seconds after 1969
Last calibration done at 1551898398 seconds after 1969
Hardware clock is on UTC time
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
/dev/rtc does not have interrupt functions. Waiting in loop for time from /dev/rtc to change
...got clock tick
Time read from Hardware Clock: 2019/03/06 18:59:12
Hw clock time : 2019/03/06 18:59:12 = 1551898752 seconds since 1969
Time since last adjustment is 354 seconds
Calculated Hardware Clock drift is 0.000000 seconds
2019-03-06 19:59:11.369732+0100

( khiraly | 2019. 03. 06., sze – 21:05 )

Ha jol latom akkor benne van a napi +-1sec pontatlansagban...:)

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Saying a programming language is good because it works on all platforms is like saying anal sex is good because it works on all genders....

"Calculated Hardware Clock drift is 0.000000 seconds"
Hol latod?

https://www.maximintegrated.com/en/products/analog/real-time-clocks/DS3…

https://www.maximintegrated.com/en/app-notes/index.mvp/id/3566
"The Most Accurate Solution—RTC/TCXO/Crystal Integration
The ideal accurate timekeeping device would be one that integrates an RTC, a TCXO, and a quartz crystal into a single package. The DS3231S is such a device. It provides unparalleled accuracy of ±2.0ppm from 0°C to +40°C, which is the equivalent of just over ±1.0 minute each year. Accuracy from -40°C to 0°C and +40°C to +85°C is ±3.5ppm, which is the equivalent of ±1.8 minute each year. The worst-case accuracy of this device is displayed in Figure 4. As mentioned in the previous section, the integrated TCXO flattens the parabolic nature of the crystal curve over temperature."

1,8*60/365=0.295890410959 masodperc/nap max az elteres ...