Deciding Micro controller

Nigel Goodwin said:

But you've got to write the code to setup and then access the RTC chip, which is likely to be MORE code than using the timer with an external 32KHz crystal, there seems little advantage at all (hence my question?).

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Yes and no. If one implements the full functionality of the RTCC in software it will be larger. If you only need a subset there will be a break even point and perhaps less code past that depending how many features are implemented.

The RTCC module is intended for applications where
accurate time must be maintained for an extended
period with minimum to no intervention from the CPU

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On a PIC without an RTCC you may have a timer active during sleep and wake the PIC to process each timer interrupt. A RTCC equipped PIC will only wake on an alarm condition. The OP's pill minder would be a good fit.

I wrote code which used Microchip RTC module. It took 99 lines of code.

For some reason, larger PIC didn't have RTC module, so I had to write my own routine. The parser routine that parses the number of seconds since fixed date into conventional date/time is 114 lines of code. It was somehow easier to write.

Maybe you could use a Pic with built in I2C serial protocol and get an I2C RTC like the ds1307 : really easy to use, 8 pins DIP package, lightweight code ( if you use PIC's built in I2C functions ). Also, if you think about enlarging your project design, you'll already have the physical I2C bus ready to go! Lots of decives work with this protocol

Jeff