>I want to test out the sounds and switch settings on this game by
>reading and writing data to certain I/O ports using my Fluke 9010a
>troubleshooter.  I looked on spies to get the memory map information,
>but I guess I need help interpretting this.  How do I figure out what
>addresses to read or write to based on this information?
>http://surfin.spies.com/arcade/simulation/gameHardware/SpaceInvaders.txt
>- or does someone have the addresses more clearly mapped out that I can
>use?

Here are my personal notes on the output section of the SI sound board.

SI does not use memory mapped I/O, so you'll need to use the I/O
or PORT function of the fluke.

If you have any questions, feel free to ask.

-Mark

Output (writes) are controlled by the "sample" signal, an addr decoder
and several latches located on the sound board.

The sample signal is the SD4 (status 4) signal, qualified by the CPU -WR
signal. When sample is active, the addr bus contains the port being
updated by the uP and the data bus contains the new contents for the port.

Ports are enabled by decoding the addr bus. An LS42 decodes A8, A9 and A10.
Note, A8 to A15 = A0 to A7 during an OUT.

Ports 2 through 6 are used. Ports 0, 1 and 7 are not used. Upper addresses
are not decoded.

P
0 - Not used
1 - Not used
2 - Shifter Control Register
3 - Sound Control Reg A
4 - Shifter Input Register
5 - Sound Control Reg B
6 - Watch Dog Reset Strobe
7 - Not used

Port 2: (Shifter Control Register)
This port is used to control the data shifter. Bits D0, D1 and D2 are
used. Bits D3-D7 are don't care.
D0=EA0 
D1=EA1
D2=EA2

Port 4: (Shifter Input Register)
This port is written with the data TO BE SHIFTED.
ALL bits are significant and presented to the shifter.

Port 6: (Watch Dog Reset)
Any OUT to this port resets the watch dog timer.

PORT 3: (Sound Control Reg A)
D0=Saucer Sound
D1=Mute
D2=Missile Sound
D3=Explosion
D4=Saucer Hit
D5=Bonus Missle Base
D6=n/c
D7=n/c

PORT 5: (Sound Control Reg B)
D0=Invader Hit
D1,D2,D3 and D4 = Invader Engine Sound (and speed)
D5=n/c
D6=n/c
D7=n/c

 


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