Apple IIe - Page 305

Appendix I 305
calling the subroutine.
• $3C-$3D first byte to store data in.
•
$3E-$3F last byte to store data in.
READ also
computes and verifies the checksum. The checksum is
calclated with a running exclusive-OR.
SETINV ($FE80/65152) A= -- X = -- Y = $3F
SETI NV sets the display format of all successive characters to
inverse video.
SETNORM ($FE84/65156) A= -- X = -- Y =$FF
SETNORM
sets the display format of all successive characters to
normal.
VERIFY ($FE36/65078) A=?? X =?? Y = ??
VERIFY is identical in operation to the monitor's verify com-
mand. Before execution of this command, certain pointers must
be set up.
• $42-$43
destination address
• $3C-$3D starting address
•
$3E-$3F ending source address
WAIT ($FCA8/64680) A= 00 X = -- Y = --
WAIT causes a delay of a specific amount of time. The length of
this delay must be loaded into the accumulator. The delay time is
calculated using the following formula.
Delay = Vi(26 + 27 A + SA2) microseconds
WRITE ($FECD/65229) A=?? X = ?? Y = ??
WRITE converts digital data into a series of tones for the cassette.
Two pointers must be set u' iJ'before calling WRITE.
• $3C-$3D address
of first data byte
• $3E-$3F address of last data byte