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8 bit IDE (XTA) Replacement Project

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This is the test equipment for the XTA to SD-Card controller, I call it XTA2SD-Card. The prototype can be seen in the middle of the picture, with a teensy LED shield and a teensy 4.1 on top.
The teensy emulates a 20 MB Harddrive, up to now each cluster is stored in a file on the SD-Card. So can fully concentrate on the XTA command implementation and can use the SD library from Arduino.

On the left the isa XTA controller, on the right the Teensy 32 bit data logger for the XTA bus.

All XTA commands needed for the boot sequence ( 00, 01, 03, 08, 0C, E4 ) are implemented in the teensy program, and the XTA2SD-Card controller does work and does read the MBR, but then
stopped and does a restart of the host. What is the reason ? How can the DMA transfer to the host been checked ? ok, another logger on the isa bus.

I have enclosed the signal list of both the XTA HDD and the XTA2SD-Card. Double signals and time stamps have been eliminated, the teensy logger can store max. 115000 signals.

Some commands are repeated more than 1000 times, this is the 00 ( Test Drive Ready ) and the 03 ( Read Status Of Last Operation ) command for drive 2 !!! The Western Digital Controller tries to find drive 2 more than 1000 times !!!
This should be eliminated in the WD BIOS, only 1 HDD is connected to the XTA bus, but this is another deal.
 

Attachments

  • XTA HDD signals.zip
    1.9 MB · Views: 6
  • XTA2SC-Card signals.zip
    1.4 MB · Views: 6
IBM PS/2 "XTA" bus has some more pins than the standard XTA bus, additional A2 and IO CH RDY and 12 V signals. So probably handles 8 Register adresses ( XTA handles only 4 ) .
 
Und jetzt auf die produktionsfähige Version warten :) / And now we we have to wait for the production version.

I'm really looking forward to it!
 
CallinElvis said:
This is the 2nd prototype card , next try is on a Schneider Euro PC II.
Click to expand...
Maybe you know better but are you sure the Schneider Euro PC II takes 8bit IDE? I'd bet it doesn't, the same external MFM HDD as the Euro PC was available for it. The Euro XT certainly does though.
 
The Euro PC has this special XTA bus for the HDD 20 where this card will be connected to ( not to the ISA bus ). The ISA bus will be left free for other ISA cards.
 
I'm sorry, but I'm only have PC10/20-III computers. But are willing to buy one for testing purposes.
 
CallinElvis said:
The Euro PC has this special XTA bus for the HDD 20 where this card will be connected to ( not to the ISA bus ). The ISA bus will be left free for other ISA cards.
Click to expand...
Oh wow so this means that even if the HD20 contains an MFM hard disk inside, it communicates/translates to an XTA bus.
I certainly wasn't aware of that, only assumed that since the HD20 is MFM the computer doesn't have XTA.
Now it makes even more sense why the went with an XTA disk on the (same period) EuroXT
 
I have a ps/2 model 30 width failed HDD,
I will say "Shut up and thake my money!!" if this project will work for this PC and you will sell a board (and eventually publish 3D print adapter) to put in HDD slot of this PC.
HDD led emulating would be a plus.
 
Owners of the Sega Teradrive would be interested as well given that it is derived off of the PS/2 Model 30-286 and uses IBM's XTA edge connector interface for hard drives.
 
The PS/2 Model 30 has a different XTA connection, not only the PINs are not compatible to the XTA interface, also the Registers are different. This needs a different software solution, although the XTA2SD PCB can be used
with minor modifications.

For detailed investigation of the communication I'm looking for a PS/2 with running HDD.
 
20MB Harddisk is working on t1000rl-hd, did not get 2x20MB working.
I am using the dos in rom and only load some files with autoexec.bat
but I have to figure out here I can get additional space.

Perhaps a multi-io card to setup a zip drive, but what about my vga-card...hmm...
 
dr.zeissler said:
20MB Harddisk is working on t1000rl-hd, did not get 2x20MB working.
I am using the dos in rom and only load some files with autoexec.bat
but I have to figure out here I can get additional space.

Perhaps a multi-io card to setup a zip drive, but what about my vga-card...hmm...
Click to expand...
My 1000rl and 1000rlx had inadequate power supplies for dual hds or certain “beefie” single hds
 
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