Commodore Amiga A500 Technical Reference Manual page 211

BIT# FUNCTION
09 DMAEN
08 DPLEN
07 COPEN
06 BLTEN
05 SPREN
04 DSKEN
03 AUD3EN
02 AUD2EN
01 AUD1EN
00 AUD0EN
Disk pointer (high 3 bits)
DSKPTH
Disk (pointer (low 15 bits)
DSKPTL
This pair of registers contains the 18-bit address of Disk DMA data.
These address registers must be initialized by the processor or Cop-
per before disk DMA is enabled.
Refresh pointer
REFPTR
This register is used as a Dynamic RAM refresh address generator. It
is writeable for test purposes only, and should never be written by
the microprocessor.
Sprite x pointer (high 3 bits)
SPRxPTH
Sprite x pointer (low 15 bits)
SPRxPTL
This pair of registers contains the 18-bit address of Sprite x
(x=0,1,2,3,4,5,6.7) DMA data. These address registers must be ini-
tialized by the processor or Copper every vertical blank time.
Sprite x vertical-horizontal position data
SPRxPOS
Sprite x vertical-horizontal
SPRxCTL
These 2 registers work together as position, size and feature Sprite
control registers. They are usually loaded by the Sprite DMA
channel, during horizontal blank; however, they may be loaded by
either processor any time.
SPRxPOS register:
BIT# SYM
15-08 SV7-SV0
07-00 SH8-SH1
SPRxCTL register (writing this address disables sprite horizontal
comparator circuit):
208
DESCRIPTION
Enable all DMA below.
Bit Plane DMA enable.
Copper DMA enable.
Blitter DMA enable.
Sprite DMA enable.
Disk DMA enable.
Audio channel 3 DMA enable.
Audio channel 2 DMA enable.
Audio channel 1 DMA enable.
Audio channel 0 DMA enable.
FUNCTION
Start vertical value. High bit (SV8) is in
SPRxCTL reg. below.
Start horizontal value. Low bit (SHO) is in
SPRxCTL reg. below.