Janus XT Memory Map

AMIGA ACCESS: Amiga Interface Offset Address = Base Addr.

  • Base Addr. + (00000 - 1FFFF) : Byte Access
  • Base Addr. + (20000 - 3FFFF) : Word Access
  • Base Addr. + (40000 - 5FFFF) : Graphic Access
  • Base Addr. + (60000 - 7FFFF) : I/O Register Access

INTERFACE MEMORY MAP:

Interface Offset Address Size Usage
00000-0FFFF 64K DISK BUFFER RAM
10000-17FFF 32K COLOR VIDEO RAM
18000-1BFFF 16K PARAMETER RAM
1C000-1DFFF 8K MONO VIDEO RAM
1E000-1FFFF 8K I0-PAGE

Kinds of memory access on the following pages:

  • B = Byte access
  • G = Graphic access
  • W = Word access

(*) selectable by BIT 5 and 6 of the MODE REGISTER

  • BIT 5 = SEL1
  • BIT 6 = SEL2

A2088XT/A2088T Memory Map PC Side

PC Address Range Size Usage

kind
of access

 Amiga Interface
Offset Address
0000-03FF 1K IO-PAGE B 1E000-1FFFF
      W 3E000-3FFFF
      G 5E000-5FFFF
        7E000-7FFFF
A0000-AFFFF 64K DISK BUFFER RAM (*) B 00000-0FFFF
    (*) W 20000-2FFFF
    (*) G 40000-4FFFF
B0000-B1FFF 8K MONO VIDEO RAM B 1C000-1DFFF
      W 3C000-3DFFF
      G 5C000-5DFFF
B8000-BFFFF 32K COLOR VIDEO RAM B 10000-17FFF
      W 30000-37FFF
      G 50000-57FFF
E0000-EFFFF 64K DISK BUFFER RAM (*) B 00000-0FFFF
    (*) W 20000-2FFFF
    (*) G 40000-4FFFF
D0000-DFFFF 64K DISK BUFFER RAM (*) B 00000-0FFFF
    (*) W 20000-2FFFF
    (*) G 40000-4FFFF
F0000-F3FFF 16K PARAMETER RAM B 18000-1BFFF
      W 38000-3BFFF
      G 58000-5BFFF

A2088XT/A2088T Memory Map Amiga Side

Amiga Interface
Offset Address		 PC Address Range Size Usage kind of
access
00000-0FFFF A0000-AFFFF 64K DISK BUFFER RAM (*) B
00000-0FFFF D0000-DFFFF 64K DISK BUFFER RAM (*) B
00000-0FFFF E0000-EFFFF 64K DISK BUFFER RAM (*) B
10000-17FFF B8000-BFFFF 32K COLOR VIDEO RAM B
18000-1BFFF F0000-F3FFF 16K PARAMETER RAM B
1C000-1DFFF B0000-B1FFF 8K MONO VIDEO RAM B
1E000-1FFFF 0000-03FF 1K I/O-PAGE B
20000-2FFFF A0000-AFFFF 64K DISK BUFFER RAM (*) W
20000-2FFFF D0000-DFFFF 64K DISK BUFFER RAM (*) W
20000-2FFFF E0000-EFFFF 64K DISK BUFFER RAM (*) W
30000-37FFF B8000-BFFFF 32K COLOR VIDEO RAM W
38000-3BFFF F0000-F3FFF 16K PARAMETER RAM W
3C000-3DFFF B0000-B1FFF 8K MONO VIDEO RAM W
3E000-3FFFF 0000-03FF 1K I/O-PAGE W
40000-4FFFF A0000-AFFFF 64K DISK BUFFER RAM (*) G
40000-4FFFF D0000-DFFFF 64K DISK BUFFER RAM (*) G
40000-4FFFF E0000-EFFFF 64K DISK BUFFER RAM (*) G
50000-57FFF B8000-BFFFF 32K COLOR VIDEO RAM G
58000-5BFFF F0000-F3FFF 16K PARAMETER RAM G
5C000-5DFFF B0000-B1FFF 8K MONO VIDEO RAM G
5E000-5FFFF 0000-03FF 1K I0-PAGE G
7E000-7FFFF 0000-03FF 1K I0-PAGE W

Last Update: 05.06.2022