SPRxPTH 120 W A Sprite x pointer (high 3 bits)
SPRxPTL 122 W A Sprite x pointer (low 15 bits)
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 initialized by the processor or Copper
every vertical blank time.
STREQU 038 S D Strobe for horizontal sync with VB and EQU
STRHOR 03C 5 D P Strobe for horizontal sync
STRLONG 03E 5 D Strobe for identification of long
horizontal line
One of the first three strobe addresses above is
placed on the destination address bus during the
first refresh time slot. The fourth strobe shown
above is used during the second refresh time slot of
every other line to identify lines with long counts
(228). There are four refresh time slots, and any
not used for strobes will leave a null (FF) address
on the destination address bus.
STRVBL 03A 5 D Strobe for horizontal sync with VB
(vertical blank)
VHPOSR 006 R A Read vertical and horizontal position of
beam or lightpen
VHPOSW 02C W A Write vertical and horizontal position
of beam or lightpen
BIT# 15,14,13,12,11,10,09,03,07,06,05,04,03,02,01,00
-----------------------------------------------------
USE V7 V6 V5 V4 V3 V2 V1 V0,H8 H7 H6 H5 H4 H3 H2 H1
RESOLUTION=1/160 of screen width (280 ns)
VPOSR 004 R A Read vertical most significant bit
(and frame flop)
VPOSW 02A W A Write vertical most significant bit
(and frame flop)
BIT 15,14,13,12,11,10,09,08,07,06,05,04,03,02,01,00
USE LOF V8
LOF=Long frame (auto toggle control bit in BPLCON0)
- Appendix A 279 -
To Next Page
Loading...
