Porkrind Dot Org: Ms. Pac-Man Memory Map

This is extremely preliminary... Bear with me....

Address Bus Cycle Affect

0000 0000 0000 0000 Read/Write Start of ROM

0011 1111 1111 1111 Read/Write End of ROM

0100 0000 0000 0000 Read/Write Start of Character Video RAM (See below)

0100 0011 1111 1111 Read/Write End of Character Video RAM

0100 0100 0000 0000 Read/Write Start of Character Color RAM

0100 0111 1111 1111 Read/Write End of Character Color RAM

0100 1000 0000 0000 Read/Write ??? Something to do with sprites ???

0100 10?? ???? ???? Read/Write End of Sprite RAM

0100 1011 1111 1111 Read/Write End of RAM

0101 0000 00XX XXXX Write out

0101 0000 0100 XXXX Write WR0

0101 0000 0101 XXXX Write WR1

0101 0000 0110 XXXX Write WR2

0101 0000 0111 XXXX Write Not Used

0101 0000 10XX XXXX Write Not Used

0101 0000 11XX XXXX Write Watch Dog Reset

0101 0000 00XX XXXX

Read

IN0 - Data bus:

`Bit`	`7`	`6`	`5`	`4`	`3`	`2`	`1`	`0`
`Meaning`	`CREDIT`	`COIN2`	`COIN1`	`DIP6`	`DOWN`	`RIGHT`	`LEFT`	`UP`

0101 0000 01XX XXXX

Read

IN1 - Data bus:

`Bit`	`7`	`6`	`5`	`4`	`3`	`2`	`1`	`0`
`Meaning`	`TABLE`	`START1`	`START2`	`TEST`	`DOWN2`	`RIGHT2`	`LEFT2`	`UP2`

0101 0000 10XX XXXX

Read

DIPSWITCH - Data bus:

`Bit`	`7`	`6`	`5`	`4`	`3`	`2`	`1`	`0`
`Meaning`	`Solder1`	`Solder2`	`DIP5`	`DIP4`	`DIP3`	`DIP2`	`DIP1`	`DIP0`

0101 0000 11XX XXXX Read Not Used

XXXX XXXX XXXX XXXX IN/OUT Interrupt Register

Character RAM Layout

Key:

This is a standard screen location.

This location exists, but is not visible on the screen.

This is not visible on the screen, nor is there any memory associated with this block. It is a placeholder.

The direction of the arrow gives the direction of the next character more or less.

Character RAM starts at 0x4000.

This is offset 0x00 in character memory. Therefore, if you write into location 0x4000 it will go here.

This is offset 0x20 in character memory.

This is offset 0x40 in character memory.

This is offset 0x60 in character memory.

The rest of the blue section continues down and to the left.

This is offset 0x3C0 in character memory.

This is offset 0x3E0 in character memory.

If you have any trouble understanding this, e-mail me, (david@porkrind.org) and I will attempt to make it more clear.

Email: david+spam@porkrind.org

Last Modified on: Apr 12, 2008 05:42am

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Character RAM Layout