Re: [hatari-devel] Real time clock support

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 06/04/2016 à 22:31, Roger Burrows a écrit :
> BTW, the existing Hatari code handles bank1 mode for writing to the alarm
> minutes register.  In case you're wondering why, Atari TOS 2.06 uses them as a
> test for whether the clock is alive.  It writes $0a to the 1-minute alarm
> register and $05 to the 10-minute alarm register (using a movep.w), and then
> reads them back.  If the values don't match, the RTC is assumed to be dead.
> This isn't documented in the datasheet.  This additional check *might* get
> added to EmuTOS at some point.
>
> A couple of other points that I came across: I don't think you need to worry
> about implementing alarm mode, because the relevant pin is not connected to
> anything.  And the RP5C15 chip is used on both the MegaST and the Mega STe.

Hi

regarding RTC clock in Mega ST(e), I see Hatari currently set unused 
bits to 1 when reading any of the register (for example, you write $0A, 
you read $FA). This is not a problem, because TOS mask unused bits, but 
was this tested on a real MegaST(e) ? I didn't see any doc about this.

If someone has a MegaST, what is the result of reading $fffc21 for example ?

Nicolas