Gen 3 RTC - SD2405 module

Has anyone had any experience with the SD2405 RTC clock modules? These include an internal backup battery and have a very low drain when power is removed. The stability is claimed to be the same as the DS3231 used on the Adafruit Precision RTC Featherwing. They only cost A$4 and come in a 16 pin DIP package which is a little easier for me to solder than the DS3231.

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@OziGreybeard, I haven’t seen any mention of that module in the forum before. There are easily-ported Arduino libraries available for it.

Did you see @rickkas7 work on the MCP79410? He has both a library and a feather wing designed for it. The chip is available in an SOIC package which can be hand soldered easily if you wish to make your own board.

Thanks. I had searched for mentions of the SD2405 and had not found any entries, hence my question. I had missed Rick’s RTC board and will have a close look.

My device is only used once or twice a day by patients and it is powered off between uses hence I need to be able to reinstate the time when it is switched on and not connected to the internet .



If you look into the RTCsync library then you will see that it is designed to support 3 different RTC ICs. If you have the datasheet for your one then it should be simple enough to ensure the correct control and status registers are setup.

@armor Which library are you referring to? I have not been succesful in looking for it. Thanks

For the RTC is a good source/template.

The RTC sync was under the data logger library so not that easy to find. Have a look in the examples.

For use with the DS3231 I have created my own stripped down RTCSync (.h/.cpp) and RTCLib (.h/.cpp) as I have added use of the alarms to create an interrupt to wake the device (Xenon) from sleep/stop mode.