Eyetech Group Ltd

Amiga Product Notes

Summary of Interface Options available

FOUR different IDE interfaces bring low cost,
reliable expansion to every A1200

Product: INT-12I-EZCDSE
EZCD-SE economy A1200 buffered interface

Product: INT-IDE-FLYR
Elbox IDE Flyer

When the Commodore engineers developed the A1200 in the early 1990’s, they had the foresight to include an IDE interface so that (relatively) low cost PC notebooks hard drives could easily be fitted. However, back then no-one ever envisaged that, six years on, A1200 owners would want to attach multiple hard drives, CDROMs, removable cartridge drives - and even CD burners such as the EZWriter - to their machines.

What Commodore left out of your A1200

However the A1200’s built-in IDE interface is minimalist in the extreme. As the Commodore design engineers only ever envisaged factory-fitted 2.5” internal hard drives being used in the A1200 - and then connected to the motherboard by a ribbon cable no longer than 2cm, they saved costs by wiring the IDE connector directly to the A1200’s main data bus, rather than via buffered line driver chips used by virtually every other computer (and as required by the relevant IDE/ATA standards).

All four IDE interfaces supplied by Eyetech - the EZCD-SE, EZCD-MK2, the IDE-Flyer and the IDE-Express - put back the bits that Commodore left out - and more.

All four interfaces provide:

• the ‘muscle’ to drive the voltages on the wires of the CDROM/HD data cable from 0v to 5v and back at up to 3 million times per second (or up to 16MB/s for the IDE-Flyer)

• a ‘gateway’ between the A1200 data bus and the IDE/ATAPI peripherals so that data is sent and received on the cable only when needed (and not continuously - whether relevant to the IDE/ATAPI devices or not - as with the standard A1200 IDE connector).

• the isolation of the Amiga custom chips from the IDE/ATAPI devices and cables to help protect your Amiga’s custom chips from damage caused by a failure of components on the IDE chain.

• In addition, all four interfaces allow you to add up to 4 IDE/ATAPI devices to your A1200 by creating two separate IDE channels, each capable of supporting a master and (compatible) slave device.

Why four Interfaces?

In any computer the internal timing mechanism is the most critical area for overall system stability. Any mismatch between the timing signals generated by the computer, and those expected by any attached peripheral - such as a hard drive or CDROM - can result in data corruption, or just failure to operate at all.

As you might expect, the faster the system and peripherals, the tighter are the tolerances on the timing signals of the A1200 and its accessories. In fact, for highly specified systems, the ‘normal’ data bus buffering (eg in the EZCD-SE interface supplied by Eyetech, and the buffered interfaces supplied by most other Amiga dealers) has to be supplemented by ‘active pull-up’ technology and extended to all interface signals - data and control. This is how the EZCD-Mk4 works.

Finally although the EZCD-MK4 interface provides more than sufficient performance for most people, if you really want to get the absolute maximum performance from your IDE peripherals you will need to bypass the A1200’s internal IDE port completely and start from scratch. This is exactly what the Elbox IDE-Flyer and the IDE-Express do.

Which Interface is best for me?

At the last count there were around 12 different A1200 motherboard revisions produced by Commodore, and many variations within these due to chip level revisions. Couple this to the different mix and variety of peripherals that individual A1200 users fit to their machines and you have nearly as many different A1200 systems as there are users. All this means is that it is not possible to be definitive about which interface is going to the the most suitable for your system. However, Eyetech’s unique compatability promise allows you the full purchase price back against your interface (less carriage) against a more highly specified interface - should you need it - within 30 days of purchase. As a general guideline you should choose the interface for your system as follows:

Interface Suitability

• EZCD-SE - 030/40 Accelerator (or slower/none)

• EZCD-Mk2 - 030/50, 040/xx, 060/xx

• IDE-Flyer - 040/xx, 060/xx, UDMA hard drive & 24speed+ CDROM

• IDE-Express - 040/xx, 060/xx, UDMA hard drive & 24speed+ CDROM

I feel the need - the need for speed

If you really want to have the best possible performance then you need the IDE-Express or Elbox IDE-Flyer - in Amiga Format’s tests it boosted performance of some hard drives by up to 600% - they rated the product at 98%. But ..... if you do decide to go this way you really need to make sure that the rest of your system is up to the job as well - otherwise you will have wasted your money.

Before ordering IDE-Express or IDE-Flyer, you should make sure that:

• Your A1200 is in a tower, with an adequate power supply (over 150W).

• You have a high-end accelerator capable of making use of all the data you throw at it.

• If you have a Commodore-manufactured A1200 with a revision 2B or 1.D.4 motherboard you have had the manufacturing timing faults corrected. (We can undertake this work for a fixed charge of �30).

• You have a modern (under 1 year old) 3.5” hard drive and CDROM capable of supporting PIO Mode 4.

• You feel confident about installing the IDE-Flyer. This involves some aptitude in DIY electronics, although no soldering is required. The IDE-Express is easier to fit but has a slightly lower performance than the IDE-Flyer.

• You are using application programs which will benefit from the faster data transfer.

The IDE-Flyer also allows hard drives over 4.3GB (the largest supported by the ROM-based FastFileSystem) to be used by ‘partitioning’ these drives into virtual drives each of less than 4.3GB.