Re: [uCsimm] IDE interface?

From: Håvard Tørring (
Date: Thu Jul 06 2000 - 03:34:58 EDT

The upper 8 bits of the 16 bit data bus are only used for data transfers.
If you drop them you will simply end up with throwing away half of the disk
space by storing 256B per sector instead of 512B. For many applications
this would be just fine.

So you will end up by needing the following lines:
(RESET) - You could probably tie this to system reset.

I think CS[1..0] can be fixed to 0x02 for most apps. You won't need IORDY
if you are not going to run this at very high speeds. INTRQ, DMARQ, DMACK
are used for DMA and interrupt handling. It's nice, but you don't strictly
need them.

You should be able to do make a IDE interface with 13 i/o lines.


At 15:35 05.07.00 -0500, you wrote:
>I was actually looking at making an IDE interface the other night. The
>IDE spec/pinout I read said that it uses 16 I/O lines, however I read
>somewhere else that it's possible to do 8bit transfers with IDEwith only
>8 I/O lines, does anyone know any more about this? This would make
>sense since CF cards seem to only use 11 I/O lines.
>Hervé BOTERMAN wrote:
>> ----- Original Message -----
>> From: Marc Nicholas <>
>> To: <>
>> Sent: Wednesday, June 28, 2000 11:57 PM
>> Subject: [uCsimm] IDE interface?
>> > Sorry if this has been discussed before...but has anyone had any job
>> > hooking up an IDE interface to the uCsimm?
>> >
>> > -marc
>> >
>> > This message resent by the list server
>> >
>> they release a soft IDE interface on a little PIC !
>> If they can do it on a PIC it should be easy to do it on uCsimm/68k !
>> The only problem is that uCsimm has to few IO to drive IDE (32bits + some
>> control lines). You have to use multiplexors/latches with levels convertor
>> (3V->5V).
>> This message resent by the list server
>* Serge Egelman
>* Broadband Network Services, Inc.
>This message resent by the list server
Håvard Tørring Norsk Elektro Optikk A/S
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