Commodore PET User Manual page 340

The screen memory, occupying memory locations 32768 through
33767, uses a different ASCII character representation from main memory.
It is a 7-bit code as shown in Figure 6-5. The eighth bit is a normal'reverse
field indicator. Note that the characters are arranged such that bits 0 through
5 represent one key on the PET keyboard, with bit 6=0 being the unshifted
character and bit 6=1 being the shifted character of the same key:
Table 6-4. ASCII Standard 7-Bit Codes
6
0 0 0 0 1
1 1
1
Bit
•
5'
0
0 1 1
0
0
1
1
3 2
~
1
0 4
0
1 0 1
0
1
0
1
0 0 0
0
NUL
DLE
SP
0 @
p
p
0 0 0
1
SOH
DC1
!
1 A
0 a q
0 0 1
0
STX
DC2
'"
2 B
R b r
0 0 1
1
ETX
DC3
'*
3 C S
c s
0 1 0
0
EOT DC4
$
4 D
T d t
0
1
0 1
ENO
NAK
%
5
E U
e
u
0
1 1
0
ACK
SYN
&
6 F V
f v
0 1 1 1 BEL ETB 7
G
W
9
w
1 0 0
0
BS
CAN
(
8
H X
h x
1 0
0 1
HT
EM
)
9
1
Y
i
Y
1 0 1
0
LF
SUB
.
J
Z
j
z
1 0 1
1
VT
ESC
+
K
[
k
(
1 1 0
0
FF
FS
<
L
\
1
1
1 1 0
1
CR
GS
-
=
M
]
m
}
1 1 1
0
SO
RS
>
N
/\ n
-
1 1 1 1 SI US
/
?
a
-
0
DEL
NUL Null DC1
Deviee control 1
SOH Start of heading
DC2 Deviee control 2
STX Sta rt of text
DC3 Deviee control 3
ETX End of text
DC4 Deviee control 4
EOT End of transmission
NAK Negative acknowledge
ENO Enquiry
STN Synchronous id le
ACK Acknowledge
ETB End of transmission block
BEL Bell. or alarm CAN
Cancel
BS Backspace
EM End of medium
HT Horizontal tabulation
SUB Substitute
LF Line feed
ESC Escape
VT Vertical tabulation
FS File separator
FF
Form feed
GS
Group separator
CR Carriage retu rn
RS Record separator
SO Shift out
US Unit separator
SI
Shift in
SP Space
DLE Data line escape
DEL Delete
327