Technical data: A500 (A2000)
Source:Amiga hardware reference manual
Complex Interface Adapters
8520 Complex Interface Adaptor (CIA) Chip.
CIA A Address Map
Byte.. Name... Data bits 7 6 5 4 3 2 1 0 or description
BFE001 pra.... /FIR1 /FIR0 /RDY /TK0 /WPRO /CHNG /LED OVL
BFE101 prb.... Parallel port
BFE201 ddra... Direction for port A (BFE001); 1=output (set to 0x03)
BFE301 ddrb... Direction for port B (BFE101);1=output (can be in or out)
BFE401 talo... CIAA timer A low byte (0.715909 MHz for NTSC; 0.709379 MHz PAL)
BFE501 tahi... CIAA timer A high byte
BFE601 tblo... CIAA timer B low byte (0.715909/0.709379MHz)
BFE701 tbhi... CIAA timer B high byte
BFE801 todlo.. 50/60Hz event counter bits 7-0 (VSync or line tick)
BFE901 todmid. 50/60Hz counter bits 15-8
BFEA01 todhi.. 50/60Hz counter bits 23-16
BFEB01 NOT USED
BFEC01 sdr.... CIAA serial data register connected to keyboard
BFED01 icr.... CIAA interrupt control register
BFEE01 cra.... CIAA control register A
BFEF01 crb.... CIAA control register B
CIA B Address Map
Byte.. Name... Data bits 7 6 5 4 3 2 1 0 or description
BFD000 pra.... /DTR /RTS /CD /CTS /DSR SEL POUT BUSY
BFD100 prb.... /MTR /SEL3 /SEL2 /SEL1 /SEL0 /SIDE DIR /STEP
BFD200 ddra... Direction for port A (BFD000); 1=output (set to 0xFF)
BFD300 ddrb... Direction for port B (BFD100); 1=output (set to 0xFF)
BFD400 talo... CIAB timer A low byte (0.71509 MHz for NTSC; 0.709379 MHz PAL)
BFD500 tahi... CIAB timer A hight byte
BFD600 tblo... CIAB timer B low byte (0.71509 MHz for NTSC; 0.709379 MHz PAL)
BFD700 tbhi... CIAB timer A hight byte
BFD800 todlo.. Horizontal sync event counter bits 7-0
BFD900 todmid. Horizontal sync event counter bits 15-8
BFDA00 todhi.. Horizontal sync event counter bits 23-16
BFDB00 NOT USED
BFDC00 sdr.... CIAB serial data register (unused)
BFDD00 icr.... CIAB interrupt control register
BFDE00 cra.... CIAB Control register A
BFDF00 crb.... CIAB Control register B
The operating system kernel has already allocated the use of several of 8520 timers:
CIAA, timer A -Keyboard. NOT AVAILABLE
CIAA, timer B -Virtual timer device used by EXEC for task switching
CIAA, TOD -50/60 Hz timer used by timer.device
CIAB, TOD - graphics.library video beam follower. This timer counts at the horizontal sync rate, and is used to syncronize graphics events to the video beam.
External Disk Connector Interface Specification
Pin# Name Note
1... RDY- I/O ID and ready
2... DKRD- I MFM input
3,4,5,6,7 - Ground
8... MTRXD- O Motor control
9... SEL2B- O* Select drive 2
10.. DRESB- O Reset
11.. CHNG- I/O Disk changed
12.. +5V PWR 870mA surge
13.. SIDEB- O Side 1 if low
14.. WRPRO- I/O Write protect
15.. TK0- I/O Track0
16.. DKWEB- O write gate
17.. DKWDB- O write gate
18.. STEPB- O Step
19.. DIRB O direction (high out)
20.. SEL3B- O* Select drive 3
21.. SEL1B- O* Select drive 1
22.. INDEX- I/O index
23.. +12V PWR 370mA surge.
Disk internal. 34 PIN RIBBON (J10)
1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33 - GND ground
6,12,14 - NC no connection
2.. CHNG*
4.. MTR0D* (LED)
8.. index
10. sel0b*
16. MTR0D*
18. DIRB
20. STEPB*
22. DKWDB*
24. DKWEB*
26. TK0*
28. WPRO*
30. DKRD*
32. SIDEB*
34. RDY*
EXTERNAL DISK CONNECTOR DEFINED IDENTIFICATIONS
$0000 0000 -no drive present.
$FFFF FFFF -Amiga standard 3.25" diskette.
$5555 5555 -Amiga 48TPI double density, double sided 5" diskette.
$AAAA AAAA -3.25" high density diskette
MOUSE/JOYSTICK/LIGHTPEN/POT CONNECTOR
PIN MOUSE... DJOYSTICK POTENC.. LIGHTPEN
1.. Vpulse.. FORWARD.. XBUTON.. UNUSED..
2.. Hpulse.. BACK..... UNUSED.. UNUSED..
3.. VQpulse. LEFT..... LBUTTON. UNUSED..
4.. HQpulse. RIGHT.... RBUTTON. UNUSED..
5.. Mbutton. UNUSED... X analog PEN PRESSED
6.. Lbutton. FIRE..... UNUSED.. PEN TRIGGER
7.. +5V..... +5V...... +5V..... +5V
8.. GND..... GND...... GND..... GND
9.. Rbutton. UNUSED... UNUSED.. UNUSED..
VIDEO CONNECTOR
1.. XCLCK* (external clock from genlock)
2.. XCLKEN* (external clock enable)
3.. RED (analog, ~1V, 75 Ohm)
4.. GREEN
5.. BLUE
6.. DI (digital, intesity)
7.. DB (digital Blue)
8.. DG
9.. DR
10. CSYNC* (composite sync)
11. HSYNC* (H sync in and out)
12. VSYNC*
13. GND FOR XCLEN* (ground for XCLEN)
14. ZD*
15. C1*
16,17,18,19,20 GND
21. A1000/A2000 -5V, A500 -12V
22. +12V
23. +5V
(note: on some old A500 XCLCK and XCLKEN are not connected to internal logic. Need to change jumpers to enable genlock)