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Alto Hardware Manual
Section 5: Miscellaneous Peripherals
35
5.0 MISCELLANEOUS PERIPHERALS
The Alto can have a number of slow peripherals which appear to programs as memory locations in the
range
177000-177777B.
The standard peripherals are described here.
5.1 Keyboard
The Alto keyboard contains
61
or
64
keys.
It
appears 'to the program as four
16
bit words in 4 adjacent
locations starting at
KBDAD (177034B).
Depressed keys correspond to zeroes in memory, idle keys
correspond to ones. Figure 6 shows layouts of the Microswitch and ADL keyboards, including key tops
and the word number, bit number corresponding to each key. All Alto Is and the more recent Alto IIs_
have Microswitch keyboards; earlier Alto lIs have ADL keyboards, which are somewhat larger and have
columns of function keys on the left and right sides.
MICROS~TCHKEYBOARD
Bit
KBDAD (177034B) KBDAD+1 (177035B) KBDAD+2 (177036B)
KBDAD+3 (177037B)
0
5
3
1
R
1
4
2
ESC
T
2
6
W
TAB
G
3
E
Q
F
Y
4
7
S
CTRL
H
5
D
A
C
8
6
U
9
J
N
7
V
I
B
M
8
o
(zero)
X
Z
LOCK
9
K
0
. <shift-left>
SPACE
10
L
. (period)
[
11
P
. (comma)
,
+
12
/
" (quote)
RETURN
<shift-right>
13
\
1
<-
<blank-bottom>
14
LF
<blank-middle>
DEL
xxx
15
BS
<blank-top>
xxx
xxx
ADL KEYBOARD
Bit
KBDAD (177034B) KBDAD+l (177035B)
KBDAD+2 (177036B)
KBDAD+3 (177037B)
0
5
3
1
R
1
4
2
ESC
T
2
6
W
TAB
G
3
E
Q
F
y
4
7
S
CTRL
H
5
D
A
C
8
6
U
9
J
N
7
V
I
B
M
8
o
(zero)
X
Z
LOCK
9
K
0
<shift-left>
SPACE
10
L
. (period)
[
11
P
. (comma)
,
+
12
/
" (quote)
RETURN
<shift-right>
13
\ (FR2)
1
<-
(FR3)
FRI
14
LF (FL2)
FR4
DEL(FLl)
FL4
15
BS
BW
FL3
FR5
FL stands for the function keys at the left of the keyboard; FR for those at the right.
Figure 6
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