APPENDIX I
When this mode is in effect, joystick information is only sent
after a joystick interrogation command ($16).
In keycode mode, stick position changes are translated
into the equivalent cursor key strokes (up arrow, right arrow,
and so on). The user may set a time factor that determines
how long the stick must be held in one position before the
cursor keycode is repeated. A velocity stick feature is imple
mented, which means that if the user holds the stick in one
position for a certain amount of time, the cursor keycodes
are repeated faster. In this mode, a button press on joystick 0
is reported as keycode $74, while a button press on joystick 1
is reported as keycode $75. For both mouse movement and
button events, break codes are sent immediately after the
make codes.
The IKBD also supports joystick monitoring mode, and
fire button monitoring mode. In these modes, the IKBD does
nothing but constantly monitor the joysticks and/or the fire
buttons, and send out status reports as fast as possible. This
mode is of questionable value for ST programmers. It dis
ables the keyboard, returns information at a rate that forces
the system to do nothing but watch the information coming
in from the IKBD, and is hard to use under TOS. These con
ditions make this mode effectively useless.
Clock Functions
The IKBD maintains a time-of-day clock that keeps track of
the time and date, to a resolution of one second. This hard
ware clock is used for the XBIOS functions Settime() and
Gettime(), but not for the GEMDOS time and date func
tions. In the new (blitter) ROMs, however, the GEMDOS
clock is set from the IKBD clock at the end of every process.
Status Functions
The IKBD provides a number of functions that allow you to
query the joystick and mouse modes, along with other pa
rameter settings. These functions even allow you to read and
set the 6301 processor's memory, as well as execute subrou
tines within that memory space.
342
To Next Page
