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Author Topic: Maximum length of 600's IDE cable?  (Read 6472 times)

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Offline Dazxy2001

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Re: Maximum length of 600's IDE cable?
« Reply #14 from previous page: February 26, 2008, 06:39:32 PM »
Quote

alexh wrote:

I've got 80-wire (round) IDE cables in my Amiga's.

I thought they were identical to 40-wire cables electronically speaking?


Yup they are, the extra wires carry additional ground signals to help stabilise data transfer at higher speeds, but below UDMA 3 and 4 theres no benefit to using these, except the round ones look nice and help airflow.
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Offline Jope

Re: Maximum length of 600's IDE cable?
« Reply #15 on: February 26, 2008, 09:44:08 PM »
Quote

rkauer wrote:
 Explaining better: some 80 wires IDE cables use "cable select" instead the "normal" straight pins. Those C-S cables must be avoided.

They all do, it's part of the ATA-66 (and higher) spec.

Why is this something to avoid? You don't have to use cable select unless you want to.

Especially with slow IDE like the Amiga's, the order of the devices doesn't make much difference.
 

Offline alexh

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Re: Maximum length of 600's IDE cable?
« Reply #16 on: February 27, 2008, 12:30:40 AM »
Quote

rkauer wrote:
some 80 wires IDE cables use "cable select" instead the "normal" straight pins. Those C-S cables must be avoided.

AFAIK all 80 strand cables are "cable select" cables (or at least they are supposed to be).

Getting technical, pin 28 is the cable select pin. The host adapter is supposed to ground this pin; if a device sees that the pin is grounded, it becomes the master device; if it sees that pin 28 is open, the device becomes the slave device. The Grey connector on an 80-strand cable has pin 28 open (unconnected) and the black connector has pin 28 wired through to the blue connector.

The only problem I know of (which isnt really a problem) is that the Amiga motherboard's IDE connector doesn't ground pin 28 as it should. It isn't connected to anything, it's just floating open (which effectively makes everything a slave).

But it doesn't matter! Most devices have jumpers to force master/slave operation.

However if you come across a device with no such jumpers, and you feel brave you can wire pin 28 to pin 30 (which is easy as they are next to each other) on the Amiga connector and now it should now be correct in terms of the IDE spec.

Such a modification should allow you to use an Amiga with these cables and two devices with their jumpers set to CS (or no jumpers at all).
 

Offline JackLTopic starter

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Re: Maximum length of 600's IDE cable?
« Reply #17 on: February 27, 2008, 11:45:13 AM »
So i tried the 30cm cable last night and it works fine  :-D
- at least with a CF card on one end. It would appear not to need shielding.

I may well get the CF adapter for PCMCIA recommended by alexh.