BASIC PR{X}RAMMING
SECTION 4.5
4,5.1
4,5.2
IJ,5, 3
VER.V09F
KEYBOAr~D
HUNTER computers are supplied with a standard QWERTY keyboard,
see Fig
2,3, KEYBOARD LAYOUT,
ELECTRICAL RE-DEFINITION
Keyboard keys are each equated to the characters they represent
by unique numerical codes, as listed in section
9,2, ASCII
CHARACTER SET. These values are defined according to the
American Standard Code for Information Interchange (ASCII).
The value returned to Basic in, for instance, an rt:CIIR statement
is the numerical equivalent of the key pressed.
The ASCII definitions of each key for the l<eyboard are contained
in
116 consecutive RAM locations named KEYBUF. The upper shift
keys are defined in the first 56 locations, followed by the 56
lower shift keys. These mer:1ory locations form a 'map' of the
physical keyboard. On power up, the HUNTER automatically
defines these locations to a standard configuration. rlowever,
the programmer has the option to be able to define special
keyboard arrangements.
The schematic of the keyboard, see section 9,6 KEYBOARD MEMORY
MAP, shows the value in KEYBUF for each key.
As an example, consider the key fourth fror.1 the left on the top
row. If it was required to program this key to be$ in upper
case and
S in lower case, t,10 Pot:e operations would be required.
POKE (KEYBUF),
36
POKE (KEYBLW + 56),83
It is important to note that on poweri.nr; up HU:ITSR, the keyboard
will revert to the standard ver~ion, The programmer should
define the special l{eyboard requirements at ;,nearly stcge in
the program and ensur,2 that the re-definition occurs each time
the prosra:n i~ run.
Trw codes u~1ed by lhe sp'2cic1J control :<eys are listed in section
2. 11,
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