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Author Topic: IO_CH_RDY on an A4000 - does it go anywhere?  (Read 1444 times)

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Offline spiranthoTopic starter

IO_CH_RDY on an A4000 - does it go anywhere?
« on: May 01, 2013, 10:28:55 AM »
Hi people,
Still trying to work out why this 4000 just doesn't grok ATAPI devices at all.

I've noticed that pin 27 (IO_CH_RDY) on the IDE bus seems to go nowhere on the schematics - is this an error? Is it supposed to connect somewhere? Seems a bit daft to have a signaled pin on the schematic that goes nowhere at all... and may be (possibly) related to my problem.

Anyone know?
Thanks!
« Last Edit: May 01, 2013, 10:34:12 AM by spirantho »
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Ian Gledhill
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Offline freqmax

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Re: IO_CH_RDY on an A4000 - does it go anywhere?
« Reply #1 on: May 01, 2013, 03:07:11 PM »
IO_CH_RDY is meant to make the bus controller (host) wait for slow units.
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Offline spiranthoTopic starter

Re: IO_CH_RDY on an A4000 - does it go anywhere?
« Reply #2 on: May 01, 2013, 04:15:46 PM »
Yes, that's what I thought. The same pin on the A1200 is called "/WAIT".

But it doesn't seem to connect to anything?!
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Ian Gledhill
ian.gledhill@btinternit.com (except it should be internEt of course...!)
Check out my shop! http://www.mutant-caterpillar.co.uk/shop/ - for 8-bit (and soon 16-bit) goodness!
 

Offline freqmax

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Re: IO_CH_RDY on an A4000 - does it go anywhere?
« Reply #3 on: May 01, 2013, 04:25:16 PM »
The designer betted that all units to be used would be fast enough?
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Offline SpeedGeek

Re: IO_CH_RDY on an A4000 - does it go anywhere?
« Reply #4 on: May 01, 2013, 07:48:14 PM »
If you check the ATA specs. you should find that I0_CH_RDY is optional for PIO 0-2 but necessary for more advanced PIO modes.
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Offline freqmax

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Re: IO_CH_RDY on an A4000 - does it go anywhere?
« Reply #5 on: May 01, 2013, 08:29:12 PM »
And A4000 only uses PIO 0-2 ? ;)
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