Amiga keyboard - reset / out of sync

[Piru]

Hello,

I'm reading my Amiga Hardware Reference Manual where it describes the keyboard. It says that some A1000 and A2000 keyboards provide a reset warning.

When the user presses CTRL + the two AMIGA keys, the keyboard responds by syncing up any pending transmission, then it sends a reset warning code to the Amiga, which can respond to this to gain up to 10 seconds of extra time in order to finish any pending operations.

But what happens if the keyboard/Amiga are experiencing the "Out-of-sync" condition? Particularly since the acknowledgement sent from the Amiga to the keyboard is under software control? Imagine that software has taken over the machine and disabled the interrupt handler for the keyboard. The Amiga will stop sending acknowledgements, but according to the manual, the keyboard must continue to try to establish synchronisation until successful.

What happens if the reset keys are pushed under such a circumstance? Will the keyboard break out of the fruitless synchronisation loop, or will it hang there forever and thus causing the reset request to be ignored?

AFAIK there's an internal watchdog timer in the keyboard logic. If nothing happens within 10 seconds the system will reset anyway.

[Piru]

This is for big box machines.

A1200 has it, too.

[Piru]

Oh yeah, mine doesn't because it has an A500 keyboard in it. :-)

Well, same here. But stock A1200 does have it ;-)