continued frompage 87
Thanks for reading, Paul!
Yep, the API stuff is really
intended for commercial
"product unique" applications.
For guys like us, the basic bare
bones, get it done stuff works
You can also use the Tera
Term Pro scripting language to
program the way the terminal
acts and responds. The
scripting commands allow you
to do things at the terminal
level that you would normally
have to program in at the PIC
or PC level.
For instance, you can
write a simple TTP script that
sends a character to the PIC
every second. Or, you could
write a script that waits for a
particular character from
the PIC to kick off a canned
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Well, "Demystifying USB to Serial"
(p. 60 Nuts & Volts 3/09) left me still a
little mystified ...
1. Wouldn't it be simpler, at least
for techie types, to use a readily-available PC-based USB to RS-232
converter? I can see for a supposedly
consumer application where you might
feel obliged to do this.
2. Even then, I would *much*
prefer the CP2102/3, its circuitry, and
anything else already built into a little
plastic box I could just mount on my
project; serial into one side, USB out
the other. I mean, as opposed to having
fun with surface mount. Am I correct
in assuming there is no such thing
available? And if so, how come?
Both of these things are still
mystifying me. I don't watch that
carefully, but I definitely feel somebody
should make the #2 gadget before me,
at any rate, stop using the #1 approach.
As far as I can tell, industrial customers,
at any rate, couldn't care less.
Thanks for reading, Mr. Owen.
The answer to Question 1 depends.
If all you really want to do is replace a
PC serial port, the USB dongle is the
way to go. I have lots of them in the
shop and use them quite often.
On the other hand, if you want
USB conversion built into your
project/product, you embed it. Or,
if you want your project/product to
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appear to the customer as a USB
plug-and-play device, you again embed
the USB interface.
The answer to Question 2 is yes.
You can buy the CP210X dev kits
from Si Labs which are USB in on one
side and RS-232 out the other. The dev
kits are intended for experimentation
and contain a ton of jumpers. You can
also get plug-in modules from DLP
These are intended for production or
The idea behind the article was to
show folks that they don't have to use
an off-the-shelf USB solution and that it
is very easy to roll your own embedded
USB interface hardware and firmware.
The article also shows the reader how
inherent USB methodology can be used
to eliminate having to include power
supply circuitry and a MAX232-based
RS-232 IC into a PIC design that has to
interface to a USB host device.
Hopefully, that clears some of
July 2009 93