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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