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EXTERNAL DISK INTERFACE CONNECTOR SPECIFICATION
The 23-pin D-type connector with sockets (DB23S) at the rear of the
Amiga is nominally used to interface to MFM devices.
EXTERNAL DISK CONNECTOR PIN ASSIGNMENT (J7)
PIN NAME DIR NOTES
--- ---- --- -----
1 RDY* I/O If motor on, indicates disk installed and up to
speed. If motor not on, identification mode. See
below.
2 DKRD* I MFM input data to Amiga.
3 GND
4 GND
5 GND
6 GND
7 GND
8 MTRXD* OC Motor on data, clocked into drive’s motor-on flip-flop by
the active transition of SELxB*.
Guaranteed setup time is 1.4 usec.
Guaranteed hold time is 1.4 usec.
9 SEL2B* OC Select drive 2.*
10 DRESB* OC Amiga system reset. Drives should reset their
motor-on flip-flops and set their write-protect
flip-flops.
11 CHNG* I/O Note: Nominally used as an open collector input.
Drive's change flop is set at power up or when no
disk is not installed. Flop is reset when drive is
selected and the head stepped, but only if a disk
is installed.
12 +5V 270 ma maximum; 410 ma surge
When below 3.75V, drives are required to reset their
motor-on flopa, and set their write-protect flops.
13 SIDEB* O Side 1 if active, side 0 if inactive
14 WPRO* I/O Asserted by selected, write-protected disk.
15 TK0* I/O Asserted by selected drive when read/write head
is positioned over track 0.
16 DKWEB* OC Write gate (enable) to drive.
17 DKWDB* OC MFM output data from Amiga.
18 STEPB* OC Selected drive steps one cylinder in the direction
indicated by DIRB.
19 DIRB OC Direction to step the head. Inactive to step
towards centre of disk (higher-numbered tracks).
20 SEL3B* OC Select drive 3. *
21 SEL1B* OC Select drive 1. *
22 INDEX* I/O Index is a pulse generated once per disk revolution,
between the end and beginning of cylinders. The
8520 can be programmed to conditionally generate a
level 6 interrupt to the 68000 whenever the INDEX*
input goes active.
23 +12V 160 ma maximum; 540 ma surge.
* Note: the drive select lines are shifted as they pass through
a string of daisy chained devices. Thus the signal that appears
drive 2 select at the first drive shows up as drive 1 select
at the second drive and so on...
- Appendix E 310 -
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...