XT-IDE  Rev 4

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


Printed on the card is "XT-IDE rev 04".

Early history

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].)

External links

• The development thread is here.

Significant changes from Rev 3

Essentially, the Rev 4 card is a Rev 3 card with the following enhancements:

• "Delay chains for improved ATA drive compatibility"
• "Jumper pads for easier installation of Slot 8 Support (GW-S8S-2) module"

Switch/jumper settings are the same.

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, or you have an Olivetti M24 or AT&T PC6300.

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

  Version of
XT Universal BIOS
on Rev 4 card
Jumper setting
of mode
on Rev 4 card
Configure 'device type' option
in 2.x.x XT Universal BIOS
Option #1 2.x.x Hi-speed "XTIDE rev2 or modded rev1"   1. Best performing option.   2. Does not work in Olivetti M24 or AT&T PC6300.
Option #2 2.x.x Compatibility "XTIDE rev1"  
Option #3 1.x.x Compatibility [ not applicable ]  

Some technical information on this subject is at here.

Switch/jumper settings

A diagram for the IDE functionality is at here
A diagram for the ROM functionality is at here

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 within the EEPROM (so that the BIOS knows which I/O addresses to use).
For example, the applicable area of the configuration/flashing tool for version 1.1.5 of the XTIDE Universal BIOS is shown at here.


See here