🚀 go-pugleaf

Hello,
  Can anyone tell me how the internal clock is implemented in the Mega STs?
I understand that it has a battery backed clock, but if this is just a
circuit to keep the keyboard chip in sleep mode ( as all the internally
fitted clock kits i have come across are ) then the current drain would be
too much for batteries to maintain for more than 2-3 weeks.  The other type
of clock I have come across uses the cartridge port - I'm sure Atari would
not start putting things in that part of the memory map.  So, does the Mega
have a clock chip sitting tucked away in some remote part of the memory map,
or does it just have a car battery with jump leads to the keyboard chip? 
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Trev..    trevor@uk.ac.ean-relay