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- USEFUL ADDRESSES
-
- No, this isn't a contact service! Here, I will list some addresses in
- memory which may be useful to programmers. Unfortunately, I don't know
- many, but here they are anyway:
-
- $FF8800 (PSG - You can do 'VU' meters with this one:
- poke $FF8800,8 : V1=peek($FF8800)
- poke $FF8800,9 : V2=peek($FF8800)
- poke $FF8800,10 : V3=peek($FF8800)
- You get a value from 0 to 15 depending on the volume of the
- particular channel).
-
- $FF8240 colour 0 (Hardware colour registers)
- $FF8242 colour 1
- $FF8244 colour 2 (Note, each colour is a 'word')
- $FF8246 colour 3 (so use DOKE or DEEK)
- $FF8248 colour 4
- $FF824A colour 5
- $FF824C colour 6
- $FF824E colour 7
- $FF8250 colour 8
- $FF8252 colour 9
- $FF8254 colour 10
- $FF8256 colour 11
- $FF8258 colour 12
- $FF825A colour 13
- $FF825C colour 14
- $FF825E colour 15
-
- $FF8203 Produces a rather interesting screen offset thingy.
- POKE $FF8203,128 is normal. Try 1,2...
-
- $FF820A You can use this one to either add that professional
- touch to a demo, or just to panic the unsuspecting ST
- user. POKE $FF820A,254 is normal. 0 flickers the
- screen, 1 slowly fades it, 5 angles the screen and
- sometimes H-shifts it. Try others...
-
- $FF820F This is the width of the screen. 0 is default, so try
- others.
-
- $9F8 Checks to see if the disk is write-protected. (Longword)
- ? LEEK($9F8) returns -1 for protected, 0 for enabled.
-
- $FB0001 Reads the sample cartridge (Byte)
-
- $4D2 A vertical-blank interrupt vector. You assign music to this
- so it plays continuously.
-
- That's all I know, I am afraid. But these ones above may keep you
- interested for a while!
-
- Article: BLACK EAGLE 1/6/93
-