ACB-4000A, ACB-4070 Hard Disk/Floppy Controller Settings and Configuration

Data bus:	None (SCSI to ST506 interface)
Size:	Drive card
Hard drives supported:	SCSI to two RLL ST506 drives
Floppy drives supported:	None

CONNECTIONS
Function	Location
20-pin data cable connector-drive 0	CN0
20-pin data cable connector-drive 1	CN1
34-pin control cable connector-hard drive(s)	CN2
4-pin connector-DC power	CN3
50-pin SCSI connector-to host adapter	CN4

SCSI ADDRESS
SCSI ID		JP5/Jumper 1	JP5/Jumper 2	JP5/Jumper 3
	0	open	open	open
	1	closed	open	open
	2	open	closed	open
	3	closed	closed	open
	4	open	open	closed
	5	closed	open	closed
	6	open	closed	closed
»	7	closed	closed	closed

USER CONFIGURABLE SETTINGS
Function		Location	Setting
»	Write precomp. disabled (ACB-4000A only)	JP2	pins 1 & 2 closed
	Write precomp. same as R.W.C. (ACB-4000A only)	JP2	pins 2 & 3 closed
	Write precomp. to all tracks enabled (ACB-4000A only)	JP2	pins 2 & 4 closed
»	DMA transfer rate is SYSCLOCK/4	JP5/jumper 4	closed
	DMA transfer rate is DATACLOCK/2	JP5/jumper 4	open
»	Extended command set enable - SASI compatible	JP5/jumper 5	closed
	Extended command set disabled	JP5/jumper 5	open
»	Not used	JP5/jumper 6	open
»	Supports the SEEK COMPLETE line during head switches	JP5/jumper 7	closed
	SEEK COMPLETE Cmd. not supported	JP5/jumper 7	open
»	Self-diagnostics enabled	JP5/jumper 8	closed
	Normal operation	JP5/jumper 8	open

MISCELLANEOUS TECHNICAL NOTES

The function of JP1 is to determine the select technique used to interface the host adapter. Soldering Pin 2 to Pin "P" allows for the "pulse" select that is used by controllers designed to work with SASI hosts. Soldering Pin 2 to Pin "H" or "L" allows for the "level" select signal used in accordance with SCSI standards.