Commodore 128 Programmer's Reference Manual page 219

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THE POWER BEHIND COMMODORE 128 GRAPHICS 209
BANK CONFIGURATION
0 RAM(O) only
1 RAM(l) only
2 RAM(2) only (same as 0)
3 RAM(3) only (same as 1)
4 Internal ROM , RAM(O), I/O
5 Internal ROM , RAM(l), I/O
6 Internal ROM , RAM(2), I/O (same as 4)
7 Internal ROM , RAM(3), I/O (same as 5)
8 External ROM , RAM(O), I/O
9 External ROM , RAM(l), I/O
10 External ROM , RAM(2)9 I/O (same as 8)
11 External ROM , RAM(3), I/O (same as 9)
12 Kernal and Internal ROM (LOW), RAM(O), I/O
13 Kernal and External ROM (LOW), RAM(O), I/O
14 Kernal and BASIC ROM, RAM(O), Character ROM
15 Kernal and BASIC ROM, RAM(O), I/O
Figure 8-1. C128 Default Memory Configurations
64K
64K
Figure 8-2. CI28 64K RAM Banks
the VIC RAM bank is selected by the RAM configuration register (bits 6 and 7). This
also is covered in detail in Chapter 13.
The configuration determined by the configuration register can be composed of
RAM and ROM, where the ROM portion overlays the RAM layer underneath, as
illustrated in Figure 8-3.