Re: Collected Comments on Home-Grown Daughterboard Design

I have a stash of 1.8..... MHz Crystals. I'm willing to donate them to the
cause if we get a group buy/kit put together for the daughter cards.

Greg

----- Original Message -----
From: Bruce D. Lightner <lightner-2huV/[email protected]>
To: ActionHack Mailing List <actionhack-W7/[email protected]>
Sent: Saturday, March 06, 2004 11:34 AM
Subject: [actionhack] Collected Comments on Home-Grown Daughterboard Design


> Scott Christensen,
>
> > At the high baud rate this board talks may need to have RTS & CTS hooked
> > up to the UART.
>
> True.  Howerver the "stock" Actiontec Daughterboard has no serial port
> "hardware flow control" hardware and/or firmware, so I left it off.
> Clearly there are unused RS-232 level-shifters in my schematic which could
> be used to add these signals in the future.
>
>  > I came across the 16c552, which is a single IC containing dual
> 16c550's.  > Is there a need for 2 serial ports?
>
> A good potential future addition I'm sure...
>
>  > http://www.exar.com/products/st16c2552v42.pdf
>  >
>  > It appears there are a lot of people making clones of this device, with
>  > all kinds of deviations on chip number in the name.
>
> "That's a fact Jack"...second sources are good!
>
> --------------------------------------------------------------------------
>
> Chris Proctor,
>
>  > I just had a look at the circuit diagram.
>  > I noticed that you had inserted a resistor (R1) in the
>  > USB5V line.  I doubt this is necessary.
>  > I was under the impression that there was already a resistor
>  > in this line on the main motherboard.  I also never saw one
>  > in the photos of the actiontec daughter card.
>
> As some of say in the newly dubbed "information technology business":
> "Safety know no season".  Therefore I added the resistor to make sure that
> the "nasty" +5V from the USB cable could not possibly damage the +3.3V
> only circuitry on the Actiontec PCB.  We can always add one of those
> useful "zero ohm" resistors if the "extra" protection resistor turns out
> to be dedundant!
>
> --------------------------------------------------------------------------
>
> Patrick McNamara,
>
>  > I have crystals in hand.  Well, actually their sitting in a bag on the
>  > kitchen counter, but I picked up three today during a trip to Fry's.
>  > I'll be working with the interface stuff tomorrow afternoon/evening.
>  > Unfortunately, being a home owner means I have to do other stuff first.
>
> Great!  Now, let's keep your priorities straight!  Fun-stuff first, "home
> work" later!
>
> P.S.- You never told me why you wanted to add GPS to this?
>
> --------------------------------------------------------------------------
>
> Best regards,
>
> Bruce
>
> --
>   Bruce D. Lightner
>   Lightner Engineering
>   La Jolla, California
>   Voice: +1-858-551-4011
>   FAX: +1-858-551-0777
>   Email: lightner-2huV/[email protected]
>   URL: http://www.lightner.net/lightner/bruce/
>
> __
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