Difference between revisions of "Memory Map"
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==Official Memory Map== | ==Official Memory Map== | ||
| − | The "official" memory map published by Mattel is included below.<br/> | + | The "official" memory map published by Mattel is included below. Note that the Intellivision was an NMOS-based system, so any memory locations that were not expilcitly mapped to a hardware unit of some sort returned all ones (1), resulting in a 16-bit value of $FFFF.<br/> |
<table border width=80%> | <table border width=80%> | ||
Revision as of 00:29, 11 January 2005
Official Memory Map
The "official" memory map published by Mattel is included below. Note that the Intellivision was an NMOS-based system, so any memory locations that were not expilcitly mapped to a hardware unit of some sort returned all ones (1), resulting in a 16-bit value of $FFFF.
| Memory Range | Accessibility | Device |
|---|---|---|
| $0000-$003F | RW, VBlank Period 1 | STIC Registers |
| $0100-$01EF | RW | Scratchpad RAM |
| $01F0-$01FF | RW | PSG Registers |
| $0200-$035F | RW | System RAM |
| $1000-$1FFF | R | Executive ROM |
| $3000-$37FF | R, VBlank Period 2 | Graphics ROM |
| $3800-$39FF | RW, VBlank Period 2 | Graphics RAM |
Additional Memory Aliases
Note that the official memory map shown above is actually incomplete, due to the fact that the STIC and the Graphics RAM chip incompletely decoded addresses that were placed on the address bus.
| Memory Range | Accessibility | Device |
|---|---|---|
| $3A00-$3BFF | RW, VBlank Period 2 | Graphics RAM |
| $3C00-$3DFF | RW, VBlank Period 2 | Graphics RAM |
| $3E00-$3FFF | RW, VBlank Period 2 | Graphics RAM |
| $4000-$403F | W, VBlank Period 1 | STIC Registers |
| $7800-$79FF | W, VBlank Period 2 | Graphics RAM |
| $7A00-$7BFF | W, VBlank Period 2 | Graphics RAM |
| $7C00-$7DFF | W, VBlank Period 2 | Graphics RAM |
| $7E00-$7FFF | W, VBlank Period 2 | Graphics RAM |
| $8000-$803F | W, VBlank Period 1 | STIC Registers |
| $B800-$B9FF | W, VBlank Period 2 | Graphics RAM |
| $BA00-$BBFF | W, VBlank Period 2 | Graphics RAM |
| $BC00-$BDFF | W, VBlank Period 2 | Graphics RAM |
| $BE00-$BFFF | W, VBlank Period 2 | Graphics RAM |
| $C000-$C03F | W, VBlank Period 1 | STIC Registers |
| $F800-$F9FF | W, VBlank Period 2 | Graphics RAM |
| $FA00-$FBFF | W, VBlank Period 2 | Graphics RAM |
| $FC00-$FDFF | W, VBlank Period 2 | Graphics RAM |
| $FE00-$FFFF | W, VBlank Period 2 | Graphics RAM |
