Re: DC IDE adapter questions

[David Brownlee <abs%netbsd.org@localhost>]

On 12 August 2012 06:10, Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> 
wrote:
> abs@ wrote:
>
>> On 7 August 2010 18:03, Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> 
>> wrote:
>> >
>> > Using correct parts doesn't mean it should just work.
>> > Actually I had to fix several connections to make DCEXT board work.
>>
>> Would you have any details on what had to be fixed to make the DCEXT board 
>> run?
>
> According to my old memo:
>
> - it's better to have external 5V power source
>   (rather than using Vcc from DC)
> - Vcc and ground lines might be weak and needs more capacitors
> - DC connector P9 should be NC and P12 should be GND
> - IDE P1 (reset) needs some power on reset signal
> - CPLD P50 (interrupt) should be connected to DC P13, not P8
> - ISA IRQ lines should have pulldown
> - It's better to ISA IRQ 5,9,10,11 rather than 3,4,6 etc
> - ISA A14 and A15 in the patern might be swapped? (not sure)
>
>> Also, would you have any objections to the patches being committed to
>> NetBSD - obviously the audience is very limited, but having the
>> patched in-tree might encourage more people to play with them.
>
> I don't think it's worth to maintain drivers that can't be
> confirmed on real hardware, i.e. no fixed specifications.
> For example, ISA interrupt mappings are changed for my DCEXT mod.

Well, the ISA mappings should be configurable via an option, but I
agree it would be of great benefit for there to be fixed hardware
specifications and multiple devices created.

> It's enough to maintain private patches for private hardware,
> unless it has fixed and written skematics and/or a certain
> number of devices are actually manufactured, like
> Neptune-X for x68k or EtherNEC and SMC_TT for atari.

Well, in this case it looks like there may be some other developers
interested in reimplementing the hardware and writing a driver under
DreamShell http://www.dc-swat.ru/forum/thread-1902.html - presumably
similar to how they produced designs for SD-via-serial and
Ethernet-via-serial adaptors for the Dreamcast, so with luck the
hardware (or at least something like it) may not remain private :)