[no subject]

I think only the top two switches are used.  The top is the write
protect switch, and the next down is the leap year switch.  One of the
others may be needed for disabling interrupts, but is not mentioned in
the manual.  Excuse my poor ASCII art:

"WRITE PROTECT SWITCH

The Apple Clock WRITE PROTECT switch must be in the
PROTECT (WP) moade at all times EXCEPT when setting
the clock.  Otherwise the clock can change time when
the computer power is turned off.  The lower two switches
are not used.
Put the switches in these positions when:" (page 6 of the Apple Clock
operating manual)

WP  -o  W        setting time
LY  -o  NLY      not leap year
    o-
    o-

WP  -o  W        setting time
LY  o-  NLY      leap year
    o-
    o-

WP  o-  W        clock is set  (normal setting)
LY  -o  NLY      not leap year
    o-
    o-

WP  o-  W        clock is set
LY  o-  NLY      leap year
    o-
    o-

where o represents switch position and - is empty.


  --Steve  (steven-nelson@uiowa.edu)