ASEM CPU 1021/A - Memory Address Map; DMA Channel Assignments

Map of memory
Asem S.p.A. 39
3F8-3FF
serial 1 port
4D0-4D1
Reserved
565-568
Watch dog
680-6FF
Reserved
778-77F
Parallel port ECP
Map of memory
The values of the addresses that appear in the tables are expressed
in hexadecimal.
Addresses
Description
000000-09FFFF
RAM dynamic
0A0000-0BFFFF
Video memory
0C0000-0CFFFF
VGA BIOS
0E0000-0FFFFF
System BIOS
100000-FFFFFFFF
Extended Memory
DMA channels
Channel
Controller
I/O
Memory
Maximum
transfer
Description
0
1
8 bit
8/16 bit
64 KB
Memory refresh
2
1
8 bit
8/16 bit
64 KB
Floppy disk Drive
3
1
8 bit
8/16 bit
64 KB
free
4
2
16 bit
16 bit
128 KB
DMA controller 1
5
2
16 bit
16 bit
128 KB
free
6
2
16 bit
16 bit
128 KB
free
7
2
16 bit
16 bit
128 KB
free