Summary: Enable a real time clock (RTC) module.
Type: Choice
Default: auto
Example: MSM6242B
Tags: hardware

Enabling a real time clock (RTC) module allows the emulated Amiga to read
the current time (automatically retrieved from the host system). When you
want to override this option, you may also have to set
[uae_chipset_compatible][] to `-`.

Value: auto ("Auto") - Automatically enable RTC module for some Amiga models.
Value: none ("None") - Real time clock is explicitly disabled.
Value: MSM6242B (Oki MSM6242B) - RTC module in A500/500+/600/1200/2000 models.
Value: RP5C01A (Ricoh RP5C01A) - RTC module in big-box Amigas (A3000, A4000).
Value: MSM6242B_A2000 (A2000 MSM6242B) - Only used in very early A2000
       revisions, not even WB 1.3 supports it.

A real time clock is enabled automatically (`auto`) for the following Amiga

* A500+, A2000 and CDTV defaults to `MSM6242B`.
* A500 defaults to `MSM6242B` only when a memory expansion is enabled.
* A1200 defaults to `MSM6242B` only when fast memory is added.
* A3000 and A4000 models default to `RP5C01A`.

# FIXME: A1200 Blizzard expansions!

Enabling warp mode can cause Workbench to not detect the RTC module
because the read time does not progress as expected (FIXME).

In versions prior to FS-UAE 2.5.19dev, A600 erroneously defaulted to having 
`MSM6242B`, while the correct default is `none` (A stock A600 does not
have any RTC module).