Re: How do I add firmware to a card?

["Michael J. Mahon" <mjmahon@aol.com>]

RedskullDC wrote:
> "Tristan Mumford" <xtristan.xmumford@xgmail.xcom> wrote in message 
> news:459bad73$0$38173$c30e37c6@lon-reader.news.telstra.net...
>
>
> > Ah nice. I'm surprised I've never seen that project page. Thanks for that. 
> > I
> > like the writeup too.
> >
> > Is there anything you haven't interfaced a flash ROM to?
>
>
> Flash roms are FUN!
>
>
> > That reminds me. I got some nice ones recently with a separately protected
> > bootblock. Problem is it needs a +12v rail to enable writing.
>
>
> The 28F circuit in the design archive is for 12V flash chips.
> Just need 2 x IN914 diodes and a switch.
> 5v through one diode directly to the programming pin
> 12v through a switch and the other diode to the programming pin.
> Diodes stop the 12V feeding back to the 5V circuit.
> You could put an LED (with appropriate series resistor) on the 12v side
> to indicate when programming voltage is present.

You'd really only need the diode in the +5v line, since the +12v
line is open anytime that +12v isn't applied.

Alternatively, an SPDT switch could be used, which would avoid any
diode forward drop issues with the +5v line.

-michael

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