Parent 
NOTE:   This web site is not some kind of 'official' documentation hub for the XT-IDE card.
It is simply the result of someone who decided to add to the documentation that exists elewhere.



VCF XT-IDE  Rev 4


This is the fourth revision of the XT-IDE card produced by the Vintage Computer Federation Forums (VCFF),  not the first nor second nor third revisions.


Identification

A photo of VCF XT-IDE Rev 4 card is here.
Printed on the card is "XT-IDE rev 04".


XT-IDE basics

Before reading further, read the web page at here, to gain information on the basics of the XT-IDE.


Early history of Rev 4

AUG2017: Printed Circuit Board (PCB) developed by glitch.
OCT2017: glitch selling kits, and assembled units, on eBay.   (Beware of inferior versions [e.g. no bypass capacitor for each IC] also seen on eBay.)


External links

• The development thread is here.
• Project files are at here.
• 'XT-IDE rev 4' link at www.glitchwrks.com/xt-ide


Significant changes from Rev 3

• "Delay chains for improved ATA drive compatibility"
• "Jumper pads for easier installation of Slot 8 Support (GW-S8S-2) module"
• The designation of the switch blocks and jumpers have changed  (!!!)


XTIDE Universal BIOS (XUB) - 'Device type' setting

When using XTIDECFG.COM to configure a freshly downloaded 2.x.x version of the XTIDE Universal BIOS for this card, you will need to alter the 'Device type' setting - see here for a screenshot.

What you set that to depends on:
• Whether your VCF XT-IDE card is jumpered for 'Hi-speed' mode or 'Compatibility' mode.
• Whether or not your VCF XT-IDE card is in an Olivetti M24 / AT&T PC6300 / Xerox 6060 / Logabax Persona 1600.

To establish the setting you need, refer to the table in the section that follows.


Hi-Speed mode versus Compatibility mode

• Just like with the XT-IDE Rev 3 card, it is expected (only for performance reasons) that the Rev 4 card be jumpered for hi-speed mode, and using a 2.x.x version of the XTIDE Universal BIOS (per option #1 in the table below).

• Compatiblity mode changes the IDE interface (specifically, its register map) to how it is on an XT-IDE Rev 1 card.  You will need to jumper your Rev 4 card for this mode if you choose to use a 1.x.x version of the XTIDE Universal BIOS.

• The four options for the Rev 4 card are show in the following table:

  Version of
XTIDE Universal BIOS
on Rev 4 card		 Jumper setting
of mode
on Rev 4 card		 Configure 'device type' setting
in XTIDE Universal BIOS
version 2.x.x for		    Comments
Option #1 2.x.x Hi-speed "XTIDE rev2 or modded rev1"   1. Best performing option.   2. Does not work in an Olivetti M24 or AT&T PC6300 or Xerox 6060 or Logabax Persona 1600.
Option #2 2.x.x Hi-speed "XTIDE rev2 (Olivetti M24)"   Only for Olivetti M24 / AT&T PC6300 / Xerox 6060 / Logabax Persona 1600.   Early 2.x.x versions of XUB lack this device type.
Option #3 2.x.x Compatibility "XTIDE rev1"  
Option #4 1.x.x Compatibility [ not applicable ]  



BIOS ROM (EEPROM) size

Just like for the Rev 2 and Rev 3 cards, either a 28C64 or 28C256 EEPROM can be used.  Set the two BIOS ROM type switches ('8K') accordingly, per the diagram at here.

Assuming that a base address of D0000 (the default) has been configured via the card's switches, the motherboard address space used by the BIOS ROM is:
28C64 (8 KB sized):   Address space = D0000 to D1FFF
28C256 (32 KB sized):   Address space = D0000 to D7FFF


I/O port range used by the IDE interface

Via switches/jumpers on the card, if you change the base I/O address of the IDE interface from the default of 300 (hex), then you will need to reflect that change within the XTIDE Universal BIOS (XUB) within the EEPROM (so that the XTIDE Universal BIOS knows which I/O addresses to use).

>>> RECONFIGURATION OF XUB VERSIONS 1.x.x

For 1.x.x versions of the XTIDE Universal BIOS (XUB), you use IDECFG.COM to reconfigure the XUB (read existing configuration, make change, write new configuration).
For example, the base I/O address area of IDECFG.COM for version 1.1.5 of the XTIDE Universal BIOS is shown at here.
The IDECFG.COM program is not generic - to play safe, use the IDECFG.COM that is supplied with the particular XUB version that you are using (it is tailored for that version of XUB).

>>> RECONFIGURATION OF XUB VERSIONS 2.x.x

For 2.x.x versions of the XTIDE Universal BIOS (XUB), you use XTIDECFG.COM to reconfigure the XUB (read existing configuration, make change, write new configuration).
For example, the base I/O address area of XTIDECFG.COM for version '2.0.0 Beta 3+ R622' of the XTIDE Universal BIOS is shown at here.
The XTIDECFG.COM program is not generic - to play safe, use the XTIDECFG.COM that is supplied with the particular XUB version that you are using (it is tailored for that version of XUB).


Switch/jumper settings

A diagram for the IDE functionality is at here     ('IDE interface')
A diagram for the ROM functionality is at here
A diagram for the 'XT Slot 8' functionality is at here

Via switches/jumpers on the card, if you change the base I/O address of the IDE interface from the default of 300 (hex), then you will need to reflect that change within the XTIDE Universal BIOS (XUB) within the EEPROM (so that the XTIDE Universal BIOS knows which I/O addresses to use) - see the 'I/O port range used by the IDE interface' section above.


Problems

See here


Other

Circuit diagram    (PDF version of KiCad file 'XT-IDE.sch')  (diagram dated about 15MAR2018)  (source of XT-IDE.sch is here)