[Soekris] 2 [serial port/LCD] questions about the net4501
chuck+soekris at 2004.snew.com
Thu Aug 12 21:38:03 UTC 2004
Quoting dan at dracosplace.com (dan at dracosplace.com):
> Thank you very much for your reply.
> It helps answer a few questions but leads me to a few more.
> > Parasiting off the serial port(s) has been an issue as it doesn't provide
> > much power at all.
> So your guess would be the the serial port would not have enough power to power
> the lcd? and if it doesn't how might you
It was in the archives recently as I was trying to get a USB->serial adapter
to work with the (1wire) weather station.
The pins are at legal (technically) RS-232 levels. But the RS-232C
specs are broad. It works fine from a 1U server system, not from
USB on Soekris. I've not checked with the 2nd serial port, yet.
I just found my stash of IDE cable connectors and intend to check
that sooner than later.
But I'm going to presume it's not powerful enough.
IT MIGHT BE FOR YOUR DEVICE.
But can your device take a DC in?
If you don't need hardware handshaking, serial becomes 3 wires (TxD,
RxD and ground). CAT 5 can shove power across easily for remote
There are options: get the serial adapter for it (a DB25) that takes in
12VDC via a plug, build a power injector for a DE9 or use a "1 wire hub".
(and also I'm leaning towards throwing this onto the home terminal server,
but have to whack the software to understand that the "device" should
not be configured for speed and other things that are iffy with
"device -> TCPSocket" programs.)
> > run power straight into (intercepted) serial
> > pins to work around that.
> ? and where is that power coming from?
Rather than using the "serial power", I can swipe power from the plug that
powers the soekris DIRECTLY - before the soekris handles it..
> > 1) "The serial port" on the soekis is a serial CONSOLE port.
> > (You don't want to use it for anything else unless you've got
> > lots and lots of good reasons and can cope with the living heck
> > - not quite hell - you'll be in for deviating)
> I was planning on installing FreeBSD and getting it setup to be able to ssh into
> before installing the lcd. would it be as bad if i could ssh into the box
> before tying up the serial console port? or would i be able to split the serial
> port? to do both
Well console, (boot, bios and other) would spit out the LCD interface. This may
be desirable. Dunno if the device needs a protocol or not. As I said, if you
really could use the lovely COM2 port sitting there.
A silent console provides challenges when it's having problems. Which will be more
> The reason i want the lcd, along with the keypad interface is so that i can have
> a temperature read out, along with possible simple system configuration
nothing that wouldn't be happy on a second serial port.
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