SECTION 6
Conversions and Interfaces
6-104 PEN*KEY
R
6200/6300 Hand-Held Computer Programmer’s Reference Guide
Keyboard Services: INT 16h
Access to the keyboard BIOS services is through interrupt 16h. The AH register
is loaded with the function number to be performed. Other registers are loaded
as required by the individual functions. Values are returned in individual
registers as defined by the functions.
Scan Codes
Table 6Ć4, below, lists the character codes for ATĆcompatible keyboards. Scan
codes containing the hidden key notation are used for the extended keys on the
101Ćstyle keyboards. Hidden key notation is defined as scan codes offered to INT
09h in the form E0Ćxx. Hidden key notation is not used for the 83/84Ćstyle
keyboards. The key number system for the 101Ćkey keyboard is defined in the
following chart:
59
60
61
62
83
106
108
110
112 113 114
115
116 117
118
119
120 121
122
123
124
125 126
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
44
46
47
48
49
50
51
52
53
54
55
57
75
80
85
76
81
86
79
84
89
90
95
100 105
91
96
101
92
97
102
93
98
103
99
104
The states of the keys are defined as follows:
"
Pressing Caps Lock shifts alphabetical keys. All other keys, defined to
return normal values, return the normal value indicated in the chart.
Pressing a shift key while in the Caps Lock state causes alphabetical keys
to return nonshifted values. All other keys, defined to return shifted
values, return their shifted value. Pressing Caps lock a second time
reverses the action.
"
Pressing Scroll Lock by itself causes no action other than the recording of
the state in the shift flags. Applications must query the state of the flag to
take advantage of Scroll Lock.
"
Pressing Num Lock causes the numeric keypad keys to return numeric
values. Pressing a shift key while in the Num Lock state causes these
same keys to return the normal values listed in the chart. Pressing Num
Lock a second time reverses the action.
"
Holding the Alt down in combination with the numeric keypad keys lets
you enter any ASCII code from 0 to 255 into the system. Register AH
returns zero and register AL returns the entered code when the Alt key is
released. If more than three digits are entered, the value returned is
moduloĆ256.
"
Combination of Alt, Ctrl, and shift key presses are given the priority of:
Alt, Ctrl, Shift. The only valid combination is CtrlĆAlt, for system reset.
"
Duplicate keys on the 101Ćstyle keyboard return the same 2Ćbyte character
code as their equivalent 83/84Ćstyle keyboard value. These duplicates
states are recorded in the shift flags. Applications must query the shift
flags to distinguish these duplicate keys.
6. Conversions and
Interfaces
