Apple Lisa - Page 22

Confidential
Lisa Hardware Reference Manual
The address $00D01C in the I/O address space clears the clock input to
the contrast latch. The address $00D01E sets the clock input, so the
MOVE instruction given above insures that there is a positive edge on
the clock input.
When the system is reset either by the RESET instruction, or by a
power-on,
t~e contrast latch is reset and the screen is cleared. The
higher the number stored in the contrast latch, the higher the
display contrast.
Page 22
7-Jul-81