[sebhc] Re: Great Idea for IDE MORE!! STATUS -- More Ideas ..

Bob Shannon bshannon at tiac.net
Mon Sep 25 18:58:13 CDT 2006

Hello list members,

I'm new here, having just gotten a working H89 (with only 1 bootable 

But I have some experience designing and building IDE controllers for my
HP minicomputers, as well as the driver software.

Take a quick look at www.pjrc.com under the 8051 development tools area.

There is software to drive a 16-bit IDE interface via an 8255 chip, using
PIO mode 0.  Not too fast, but its bullet proof.

I used a pjrc.com board with hardware added to talk to a generic HP 
board to implement my HP IDE disk controller, letting the 8052 take care of
mapping the IDE drives LBA format into addressable blocks for the HP 

Something very similar could be done to tie a pjrc.com 8052 board to the 
All the low-level IDE driver code is right there, ready to go.

Or, simply re-write the low-level IDE driver code, moving it from the 8052
to the Z80.

----- Original Message ----- 
From: "bill malcolm" <wm65805 at hotmail.com>
To: <sebhc at sebhc.org>
Sent: Monday, September 25, 2006 5:50 PM
Subject: Re: [sebhc] Re: Great Idea for IDE MORE!! STATUS -- More Ideas ..

> HI:   Idea  use  IDE  as only 8 bit.  This is done sending a cmd to IDE
> drive. Then you can have 2  volumes by accessing  as below.
>    Normal IDE sector   or block is  512 bytes SO...
> 1st volume  uses  bytes  0-254
> 2.nd volume uses bytes  255-511
> bill ..
> more later...
> ----- Original Message ----- 
> From: "Lee Hart" <leeahart at earthlink.net>
> To: <sebhc at sebhc.org>
> Sent: Saturday, September 23, 2006 1:20 PM
> Subject: Re: [sebhc] Re: Great Idea for IDE MORE!! STATUS -- More Ideas ..
>> dwight elvey wrote:
>> > What is the problem with going from a 8 bit bus to a 16 bit device?
>> > You just need an extra port and an extra latch going both ways.
>> > This is not rocket science to add this simple hardware. The entire
>> > world of IDE devices are then open to you.
>> I agree. This is fairly straightforward to do. It takes about twice as
>> many chips, but they are relatively inexpensive. As you say, then you
>> have a "normal" 16-bit interface to the IDE, so the documentation on
>> how to talk to an IDE device will apply. Or, you could reverse-engineer
>> someone's IDE device software driver, if you were desperate enough :-)
>> The skeptic in me says that the published specs for IDE devices are
>> probably obscure, incomplete and inaccurate. If it were me, I'd build a
>> little logic analyzer to capture the 16-bit words going back/forth
>> between a PC and its IDE drive when I did a read or write. Then, I would
>> program the Z80 to send exactly those commands, in the same order,
>> REGARDLESS of what the published specs say!
>> --
>> Ring the bells that still can ring
>> Forget the perfect offering
>> There is a crack in everything
>> That's how the light gets in    --    Leonard Cohen
>> --
>> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>> --
>> Delivered by the SEBHC Mailing List
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