Re: DIY ISA backplane

[Sergey <skis...@gmail.com>]

Yes, post codes display is definitely a nice idea... and it is not too
complicated to build... something like one 74LS688 for address decode
a pair of 74HCT4511 7-segment latches/decoders/drivers, with matching
LED displays and resistor arrays.
Unfortunately 74HCT4611 will not decode numbers above 09h, but
fortunately we define what post codes to use :-)

Thanks,
Sergey

On Sep 25, 10:50 pm, opticpow <wa...@ingram.net.au> wrote:
> Hi Wayne,
>
> I think your idea of having the "post card" build into the back plane would
> be a good idea. I think the FDC would be better as a card to allow more
> flexibility.
>
> Cheers,
>
> Wayne.
>
>
>
>
>
>
>
> On Wednesday, September 26, 2012 12:54:49 PM UTC+10, Wayne Warthen wrote:
>
> > Hi Sergey,
>
> > I would certainly be interested in the backplane as well.  Including
> > serial ports and FDC seems useful, but I don't think it is critical since
> > those are easy to add with adapters.  The only other idea that occurred to
> > me was possibly including a pair of POST diagnostic HEX digit leds.  It is
> > certainly not a big deal to me, just an idea.
>
> > The only critical thing to me is that it be ATX case mountable.
>
> > Thanks,
>
> > Wayne
>
> > On Tuesday, September 25, 2012 12:43:38 PM UTC-7, Sergey wrote:
>
> >> Hi,
>
> >> Several people asked me about getting an ISA back plane. While it is
> >> possible to buy one, some folks would like to build one themselves.
>
> >> So I am wondering how many people would like to build one?
>
> >> Also I would like to collect various ideas for making the backplane.
>
> >> Here is what I have in mind so far:
>
> >> - Minimally sized Micro ATX board  (9.6" x 6.7" or so). It is possible
> >> to make the board even smaller, only using the PCB space needed for
> >> connectors and other components, but yet keep the ATX - compatible
> >> mounting holes.
> >> - 5 or 6 ISA slots. Note that Micro ATX only allows 4 slots, so if
> >> using a case only 4 slots will be exposed on the back side. But still
> >> it should be possible to use the remaining slots for cards that don't
> >> have connectors on the back side, for example the XT-IDE card.
> >> - ATX power connector and power on circuit (so it will work with a
> >> momentary switch normally found in ATX cases)
> >> - Minus 5V regulator (convert -12V to -5V). Most modern ATX power
> >> supplies don't provide -5V (it is optional), but yet some ISA cards
> >> use it. This circuit could be optional with a jumper to select -5V
> >> source (ATX power supply or the backplane regulator)
> >> - Onboard FDC and UART... maybe a couple of UARTs. I am not sure about
> >> this one... an alternative would be making an FDC/UART ISA card, which
> >> is more universal approach. I this case it is possible to provide two
> >> DE9F serial port connectors with 5x2 headers connected to them (for
> >> example to plug the XT-IDE V2 serial interface).
>
> >> Any suggestions?
>
> >> Thanks,
> >> Sergey