Commodore PET User Manual page 317

Display
Screen
,
14K ROM 8K" RAM
4K
Cassette
(BASIC
(Storage and
Video RAM
Tape
.--
--,
and OS) User Pgm)
Unit
1
t
t
4K/8K
1
• 16K/3
Cassette
-
~
Tape
Interface
6502
Micro-
~
2K
...
IEEE 488
processor
1/0
Interface
~
Parallel
User Port
r--
1.--,
r--
1.--,
,
Expansion Expansion
1 ROM 1
1
RAM 1 Keyboard
1 12K 1 1
24K" 1
L. _____ .J L _____
.J
"Varies from 4K RAM with 28K Expansion RAM
to 32K RAM with no Expansion RAM.
Figure 6-1. PET Black Diagram
Table 6-1. PET Memory Allocation by 4K Blacks
2K
Memory
Start Address
Block
Description
Type
Decimal
Hexadecimal
0
RAM
0
0000
Working storage. start of text
1
RAM
4096 1000
Text and variable storage (8K only)
2
-
8192
' O OO}
3 - 12288 3000
4 - 16384 4000
Expansion RAM
5
-
20480
5000
6
-
24576
6000
7
-
28672 7000
8
RAM
32768 8000
Screen Memory
9
-
36864
9000 }
10
-
40960
AOOO
Expansion ROM
11
-
45056
BOOO
12
ROM
49152 COOO
BASIC (principally statement interpreter)
13
ROM
53248
0000
BASIC (principally math package)
14 ROM
57344
EOOO
Screen Editor (2K)
1/0
59392
E800
1/0 Memory (2K)
15
ROM
61440 FOOO
Operating System (OS)
304