Exile In Paradise

Stranded on Earth...

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sst-6809:memory_map [2024/10/13 17:05] – added some ASSIST09 ram notes robertsst-6809:memory_map [2024/10/13 21:30] (current) – add note for ASSIST09 expansion ROM area robert
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 ====== Memory Map ====== ====== Memory Map ======
  
-^ Start - End ^ Purposes ^ +^ Use  ^  Start - End  ^ Implementation  ^ 
-| 0000 - DFFF | [[#56K NVRAM]] | +| RAM |  0000 - DFFF  | [[#56K NVRAM]] | 
-| D000 - D0FF | ASSIST09 working RAM, stacks and vector copies | +| ::: |  D000 - D0FF  | ASSIST09 working RAM, stacks and vector copies | 
-| E000 - E3FF | [[#Main Bus Select 0 1K]] | +| I/O |  E000 - E3FF  | [[#Main Bus Select 0 1K]] | 
-| E400 - E7FF | [[#Main Bus Select 1 1K]] | +| ::: |  E400 - E7FF  | [[#Main Bus Select 1 1K]] | 
-| E800 - EAFF | unassigned | +| ::: |  E800 - EAFF  | unassigned | 
-| EB00 - EBFF | [[#ACIA Select 256b]] | +| ::: |  EB00 - EBFF  | [[#ACIA Select 256b]] | 
-| EC00 - EEFF | unassigned | +| ::: |  EC00 - EEFF  | unassigned | 
-| EF00 - EFFF | [[#Memory Latch Select 256b]] | +| ::: |  EF00 - EFFF  | [[#Memory Latch Select 256b]] | 
-| F000 - FFFF | [[#EEPROM 4K]] | +| ROM |  F000 - FFFF  | [[#EEPROM 4K]] | 
-| - F000 - F3FF | [[ASSIST09]] Expansion ROM area | +| ::: |  F000 - F3FF  | [[ASSIST09]] Expansion ROM area (unused) | 
-| - F800 - FFFF | [[ASSIST09]] | +| ::: |  F800 - FFFF  | [[ASSIST09]] | 
-| - FFF0 - FFF1 | HD6390 Illegal Opcode/Divide By Zero Trap vector (FFD4) | +| MPU |  FFF0 - FFF1  | HD6390 Illegal Opcode/Divide By Zero Trap vector (FFD4) | 
-| - FFF2 - FFF3 | SWI3 vector (FFD8) | +| ::: |  FFF2 - FFF3  | SWI3 vector (FFD8) | 
-| - FFF4 - FFF5 | SWI2 vector (FFDC)| +| ::: |  FFF4 - FFF5  | SWI2 vector (FFDC)| 
-| - FFF6 - FFF7 | /FIRQ vector (FFE0) | +| ::: |  FFF6 - FFF7  | /FIRQ vector (FFE0) | 
-| - FFF8 - FFF9 | /IRQ vector (FFE4) | +| ::: |  FFF8 - FFF9  | /IRQ vector (FFE4) | 
-| - FFFA - FFFB | SWI vector (FFE8) | +| ::: |  FFFA - FFFB  | SWI vector (FFE8) | 
-| - FFFC - FFFD | /NMI vector (FFEC) | +| ::: |  FFFC - FFFD  | /NMI vector (FFEC) | 
-| - FFFE - FFFF | /RESET vector (F837) |+| ::: |  FFFE - FFFF  | /RESET vector (F837) |
  
 The 2.0 board is hard wired for "Exxx" selects in the map above. The 2.0 board is hard wired for "Exxx" selects in the map above.
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 The Memory Latch Select allows mapping one of eight 4KB sections of the EEPROM into the memory range $F000-$FFFF which includes the MPU interrupt vectors. The Memory Latch Select allows mapping one of eight 4KB sections of the EEPROM into the memory range $F000-$FFFF which includes the MPU interrupt vectors.
 +
 +Make use of the boot ROM select jumper(s).
 +
 +The 2.0 can boot from 4 different segments, the 2.1 only 2.
 +
 +But the current EEPROM only has ASSIST09 burned into it.
 +
 +The "external ROM" is just the unused space in the other half of the 4k boot ROM.
 + 
 +Ken just never put anything there.
 +
 +At some point Ken could burn another boot into an EEPROM.
 +
 +The PTM on the Mezz board can support tracing with ASSIST09, but it needs a jumper to put its interrupt on NMI.
  
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