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CHIP REGISTER MAP
Each 8520 has 16 registers that you may read or write. Here is the list
of register and the access addresses of each within the memory space
dedicated to the 8520:
Register
RS3 R52 RS1 RS0 (hex) NAME MEANING
------------------------------------------------------------
0 0 0 0 0 pra Peripheral data register A
0 0 0 1 1 prb Peripheral data regigter B
0 0 1 0 2 ddra Data direction register A
0 0 1 1 3 ddrb Direction register B
0 1 0 0 4 talo Timer A low register
0 1 0 1 5 tahi Timer A high register
0 1 1 0 6 tblo Timer B low register
0 1 1 1 7 tbhi Timer B high register
1 0 0 0 8 todlow Event LSB
1 0 0 1 9 todmid Event 8-15
1 0 1 D A todhi Event S
1 0 1 1 B No connect
1 1 0 0 C sdr Serial data register
1 1 0 1 D icr Interrupt control register
1 1 1 0 E cra Control register A
I 1 1 1 F crb Control register B
SOFTWARE NOTE:
The operating system kernel has already allocated the use of
several of the 8520 timers.
CIAA, timer A - keyboard (used continuously to handshake
keystrokes). NOT AVAILABLE.
CIAA, timer B - Virtual timer device (used continuously
whenever system Exec is in control; used
for task switching, interrupts and timing).
CIAA, TOD - 50/60 Hz timer used by timer.device. The
A1000 uses power line tick. The A500 uses
vertical sync. The A2000 has a jumper
selection.
CIAB, timer A - not used
CIAB, timer B - not used
CIAB, TOD - graphics.library video beam follower. This
timer counts at the horizontal sync rate,
and is used to synchronize graphics events
to the video beam.
Note that previous editions of this chart were incorrect.
- Appendix F 319 -
Содержание Amiga A1000
Страница 1: ...AMIGA HARDWARE REFERENCE MANUAL 1992 Commodore Business Machines Amiga 1200 PAL...
Страница 20: ...Figure 1 1 Block Diagram for the Amiga Computer Family Introduction 11...
Страница 21: ...12 Introduction...
Страница 72: ...Figure 3 12 A dual Playfield display Playfield Hardware 63...
Страница 87: ...Figure 3 24 Horizontal Scrolling 78 playfield hardware...
Страница 101: ...92 Playfield Hardware...
Страница 199: ...Figure 6 9 DMA time slot allocation 190 Blitter hardware...
Страница 203: ...Figure 6 13 Blitter Block Diagram 194 Blitter Hardware...
Страница 229: ...220 System Control Hardware...
Страница 246: ...Figure 8 8 Chinon Timing diagram cont Interface Hardware 237...
Страница 265: ...256 Interface Hardware...
Страница 289: ...280 Appendix A...
Страница 297: ...288 Appendix B...
Страница 298: ...APPENDIX C CUSTOM CHIP PIN ALLOCATION LIST NOTE Means an active low signal Appendix C 289...
Страница 302: ...APPENDIX D SYSTEM MEMORY MAP Appendix D 293...
Страница 343: ...334 Appendix F...
Страница 351: ...342 Appendix G...
Страница 361: ...352 Appendix H...
Страница 367: ...358 Appendix I...