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Re: MSP430 RTC

Other Parts Discussed in Thread: MSP430F47163

Hi aLL,


      Currently ,we are in Gas Meter design with MSP430F47163, WE want some data needs to be updated like Time & Date, so can we use inbuilt RTC in MSP430, how do i achieve this. what happens if we remove power to microcontroller. OR should we use external RTC & Battery for this.  


whether we can use separate battery only for inbuilt RTC or not.






  • The RTC in the 4x series does not have a separate battery backup for the RTC function. Basically, this RTC is just a counter with specialized counting registers that is otehrwise not more than the other timer/counters.
    The RTC_A in the 5x series has additional trimming features, but only the RTC_B in some 5x/6x devices has a separate backup battery input that is used only for driving the crystal and the RTC part.

    Personally, I prefer an external RTC as it is too easy to accidentally reset the internal one. Many years ago I mad my first RTC moduel for the C64 based on the PCF8583 RTC/Ram chip with I2C protocol. I still use it for my projects that require an RTC. Those old RTC modules did run on a small button battery (AG13) for several years. Currently I use small supercaps which drive the same old I2C chip for several days to bridge shorter power losses (e.g. due to position change) of our sensor network access points.

    The internal RTC_A of the 5438 serves as timer for my preemptive multitasking scheduler. :)