• Please review our updated Terms and Rules here
  • Exhibitor application for VCF West 2022 is now open! If you are interested in exhibiting, please fill out the form here.
  • Here are the results of the VCF East 2022 Post Event Survey: Survey Results

IBM PS/2 Model 70 Fixed Disk Adapter Technical Reference

seeker010

New Member
Joined
Mar 31, 2016
Messages
5
Location
USA
Does anyone have the technical reference manual for signals needed to interface with the DBA hard drive connector on the model 70? (would also apply to 50z and 55sx I believe). I'm running running a 70 with 2 memory expanders and a XGA card. Ideally would rather just shim in a ARM/FPGA to SD card rather than waste a slot on a scsi adapter. Currently running a Jaz drive off the parallel port, but I don't think OS2 would play well with that setup.
 

njroadfan

Veteran Member
Joined
Jan 21, 2011
Messages
1,523
Isn't DBA just a modified Microchannel slot pinout? Sorta like the MCA equivalent of IDE (which is basically ISA with I/O addresses decoded and condensed to 3 pins and one IRQ line).
 

seeker010

New Member
Joined
Mar 31, 2016
Messages
5
Location
USA
yes, but I believe it uses encoding similar to the st412r using MFM RLL 27. also according to the model 70 ref doc I have address lines 12,14,15 and the ones that are active. I'm assuming that's what the I/O has been condensed down to, but not sure how to decode that. been trying to find a technical reference to make sense of it.
 

ardent-blue

Experienced Member
Joined
Jan 2, 2015
Messages
362
Does anyone have the technical reference manual for signals needed to interface with the DBA hard drive connector on the model 70? (would also apply to 50z and 55sx I believe). I'm running running a 70 with 2 memory expanders and a XGA card. Ideally would rather just shim in a ARM/FPGA to SD card rather than waste a slot on a scsi adapter. Currently running a Jaz drive off the parallel port, but I don't think OS2 would play well with that setup.

Mission's a secret, destination's unknown...

8573-P70, 8550z, 8555sx, 8570 -AND- TAA-DAA the 8590-402!

http://ps-2.kev009.com/ohlandl/8573/8573-P70.html
S68X-2377-00 IBM Personal System/2 Model P70 Technical Reference Apr 1989
P70 Supplement for the Hardware Interface and BIOS Interface Technical Reference
DASD Storage Interface Specification Micro Channel (REV 2.2)

http://ps-2.kev009.com/ohlandl/9590/Model_90_Type-0.html

It would be uber-geek to add 1GB via DBA-ESDI.
 

seeker010

New Member
Joined
Mar 31, 2016
Messages
5
Location
USA
Thanks! this is very helpful. I think I may be on to something, at least in my head. Does anyone know where I can get a custom pcb made (for cheap) that has the right pitch for the edge connector? I need the I/O connectors changed to pins, and the power/ground routed to a standard 4 pin power plug. Wouldn't mind if someone created the design :xmas:


Mission's a secret, destination's unknown...

8573-P70, 8550z, 8555sx, 8570 -AND- TAA-DAA the 8590-402!

http://ps-2.kev009.com/ohlandl/8573/8573-P70.html
S68X-2377-00 IBM Personal System/2 Model P70 Technical Reference Apr 1989
P70 Supplement for the Hardware Interface and BIOS Interface Technical Reference
DASD Storage Interface Specification Micro Channel (REV 2.2)

http://ps-2.kev009.com/ohlandl/9590/Model_90_Type-0.html

It would be uber-geek to add 1GB via DBA-ESDI.
 

seeker010

New Member
Joined
Mar 31, 2016
Messages
5
Location
USA
I think I have devised a strategy with the IBM documentation and it seems reasonably doable, but wouldn't mind some forum help.
Code:
1) create a gold finger pcb that connects to the DASD or 16 bit MCA slot (need to find a source for a cheap one to do dev work on. Any ideas?)
2) connect control lines to MCA microcontroller; I know of the P82C612. Are there any others?
3) connect data/address/book keeping pins to GPIO pins of FPGA, with necessary pull up resistors on the right lines (maybe the Spartan ones with 100+ GPIO pins @ 100MHz)
4) program FPGA to translate IO signals to SD card or CF card via SATA->SATA-IDE bridge (unless someone knows of any IDE microcontrollers for sale)

need some more documents and help for the below:
5) create audio processing code for FPGA
6) connect to OPL3
7) write FPGA code for wavetable synthesis and uploading/storing of Sound Fonts in ROM and RAM
8) connect to AC97 codec with integrated DAC/ADC
9) port MCA microcontroller logic to FPGA software so there's no reliance on legacy parts
10) ...
11) profit
 

njroadfan

Veteran Member
Joined
Jan 21, 2011
Messages
1,523
A PCI prototyping PCB with the edge connector cut down to size will likely work for MCA prototyping.
 
Top