7568 DASD Module

@8EFD.ADF SCSI Cached Disk/Diskette Controller

DASD Module
Open DASD Module
Opened DASD Layout
HD Rails
HD Drive Shapes Supported
Floppy Drive Stuff
Drive Spacer
ADF Section

DASD Module (#6222)

CR1 Run/Check LED
CR2 Drive in Use LED
F1 125 V / 1.5 A Littelfuse
F2,3 125 V / 2 A Littelfuse
J1 DB26 port for Setup Aid
J2 C60 port for SCSI
P1,2 Backplane connectors
P3,4,6 Drive power connections
P5 40-pin FD header (8570 style)
P7 Unknown 4-pin header
P8 SCSI connector
RP1 Termpack
U10 80C188
U17,21 30-pin SIMM socket
U29 Hitachi HM62256LFP-12T
U31 20.0 MHz osc
U37 15F7917
U43 SCSI µcode ROM
U52 15F6903 SCSI Cache/data flow controller
U53 33F6715 SCSI MCA iface/BM DMA controller
U57 24.0 MHz osc
U62 82077-1 Floppy controller
U63 Adaptec AIC-6250EL

U43 SCSI µcode ROM - D27512-200; sticker 57F2716, internally 57F2717

The Disk Module consists of a double-wide shroud and a Disk/Diskette Adapter Card. The Disk/Diskette Adapter Card contains 0.5MB of DASD Cache Memory (should take two 1MB Spock compatible 30 pin SIMMs), and supports up to two 1.6" high 3.5" drives and a 1.44MB Diskette Drive installed inside the shroud. The DASD Module has a C60 SCSI port on the bottom and a triple-row DB26 (floppy port for setup aid?).

SCSI BIOS Upgrade Ready

The upgrade SCSI BIOS chips for the SCSI and SCSI w/cache (92F2244/92F2245) work in this board, and probably all others. If you look at the SCSI w/cache, single oscillator, the parts are the same.

Note: PS/2 adapters should not be installed in the slot #9 position. This is due to limitations with setup and diagnostic code recognizing such adapters in that position.

2.88MB Support

The D40 (possibly C40 as well) support the 2.88MB floppy. It's in the setup options...

Set ID

Your C: MUST be set to ID6, a second HD MUST be set to ID5, as the setup lacks selectable start sequence. The SCSI adapter itself is ID7.

Something I haven't seen- if you add an auxiliary DASD module to slots 1 and 2, the drives must use ID0 to ID4. The drives within the Auxiliary DASD module are considered as external SCSI devices.

Open the DASD Module

Pull up on one of the ears and twist the latches out. (Important to remove them!). Now go to the back of the module and undo the two catches. Can't miss them. The DASD module is the only one to have them. Pull the cover out. It will pivot on the two tabs at the front edge.

Note: If you left the latches on, this will NOT work.

DASD Layout 

Once you open the DASD up, the top swings back, held at the bottom by the data and power cables.

HD Rails

Hard Drive Shapes Supported

The 7568 requires the squarish 0661/0662/0663 drives to fit the 7568 specific drive rails. The mounting holes on the 1" high 0662 do NOT match. You can drill a new pair of screw holes in the rails, but keep this in mind- the on-board SCSI is 50 pin, so why not keep with the 0661/3 1GB-2GB range?

Floppy Drive

The drive in the 7568 is used in the Model 70, PN 15F7503. It is a modified ALPS DFP723D12F with a PCB screwed in place on the top. The drive that came with an 8570 has a clear plastic sled screwed on, but the same PN 15F7503. Another 8570 drive is a Mitsubishi MF355C-599MB.

Some pictures stolen from Alfred Arnold's page:

Remove the Floppy Drive

Remove the clear plastic spacers between the drive latches. Unscrew the two screws on the outside of the shroud (they screw into the FD's bottom!). Spread the two sets of latches one side at a time, pulling up on the FD. Once the FD rails are past the latch, pull it back and up.

The floppy rails are held on with two screws per side. The funky thick black bezel will come off quite easily AFTER you unscrew the front rail screw. Trust me. Do NOT try to pry the thick bezel off, it is rather ready to fall off once the front screws are half way out.

Drive Spacer

The important dimension is along the top. Take all your measurements from that edge. The spacer is pictured upside-down to emphasis the critical edge.

The 5 mm slot can be a bit wider, the 12 mm slot depth may be deeper. Round off all sharp corners.

AdapterID 8EFD SCSI Cached Disk/Diskette Controller

SCSI Adapter Memory Location
   Selects 32kb memory block used for it's BIOS ROM. There are five memory ranges.
     <"Segment C000" (mem c0000-c7fff)>, C400 (c4000-cbfff), C800 (c8000-cffff), Segment CC00 (cc000-d3fff), D000 (d0000-d7fff), D400 (d4000-dbfff), D800 (d8000-dffff), "ROM Disabled"

SCSI I/O Address
   Choose the I/O address for each adapter
     <"3540-3547" (io 3540h-3547)>, 3548-354F, 3550-3557, 3558-355F, 3560-3567, 3568-356F, 3570-3577, 3578-357F

SCSI Arbitration Level
   Select the arbitration level that SCSI will use to transfer data.
     <"Level C" (arb 12)>, D, E, 1, 3, 5, 6, 8, 9, A, B

SCSI Adapter Fairness On/Off
   Whether the adapter releases control of the bus when it has been using it exclusively.
     <"On" >, "Off"

ROM Wait State Disable
   Enable/Disable ROM Wait State
     <"Enable Wait State">, "No Wait State"

SCSI Adapter Address (ID)
   Change the SCSI ID of the adapter.
     <"7">, "6", "5", "4", "3", "2", "1", "0"

Address Burst Boundary
Determines the maximum number of bytes per burst
     < "No Boundary">, "32-Byte Boundary", "64-Byte Boundary", "128-Byte Boundary"

Diskette DMA Arbitration Level
   DMA channel diskette adapter will use to transfer data.
     <"Shared level 2 only" (ARB SharedArb 2)>

Diskette Adapter Fairness On/Off
   Whether diskette adapter releases control of the bus when it has been using it exclusively.
     <"Off">, "On"

Diskette Primary/Alternate Addresses
   Primary or secondary address range of the diskette portion.
     <"Primary 03F0-03F7" (io 3F0-3f7 int 6)>, "Alternate 0370-0377" (io 370-377 int 6)

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

Ardent Tool of Capitalism is maintained by Tomáš Slavotínek.
Last update: 08 May 2024 - Changelog | About | Legal & Contact