Re: SERIAL PORTS (was: cannot connect gto CP3 to the SKy 6)


Christopher Erickson
 

There are microcontroller peripheral support chips (dedicated task
microcontroller) that do all of the Ethernet communications and this is a
common approach for doing Ethernet with microcontrollers. They communicate
with the primary microcontroller via I2C, RS-232 or 4/8/16 bit parallel bus.

Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738
www.summitkinetics.com

-----Original Message-----
From: ap-gto@yahoogroups.com [mailto:ap-gto@yahoogroups.com] On Behalf Of
Louis Mamakos
Sent: Sunday, October 21, 2012 4:53 AM
To: ap-gto@yahoogroups.com
Subject: Re: [ap-gto] SERIAL PORTS (was: cannot connect gto CP3 to the SKy
6)

I completely support moving to an Ethernet interface on the mounts! That
might be something to help justify the upgrade from my GTOCP2, recently
repaired after zapping the RS232 drivers, likely due to a nearby lightning
strike. That's a another nice property of 10Base-T, 100Base-TX, etc.
twisted-pair ethernet: transformed coupled physical interfaces to avoid all
sorts of ground-loop issues on the signal cables.

A-P will have to move to a different embedded CPU that sport Ethernet MAC
interfaces; I don't think that Microchip has any for their PIC series
devices. I've been doing some work with some STM32F1xx and STM32L15x series
ARM Cortex-M3 based devices, and they sure are nice!

Louis Mamakos


On Oct 17, 2012, at 6:46 PM, Chris1011@aol.com wrote:


I had a very frustrating night a few weeks ago with USB. While trying to
connect my Dell laptop to my imaging system (QSI683 and Lodestar) I could
not communicate with the Lodestar. I tried every USB port on my laptop, but
to no avail. I finally ditcvhed my Dell and borrowed Howard's laptop. Lost
several hours of darkness in the process. Later on I noticed that some of
the USB connectors on my Dell had a little plastic spacer missing -
apparently broken off. So those are now out of commission.

One other thing about USB - our electronic engineer, who works on
aerospace equipment, said that USB is not rated for outdoor use. Humidity
and cold temperatures can cause failure. It is absolutely forbidden in any
equipment that would go on an airplane.

USB also cannot be used long distance. You can be 200 ft away with serial,
but not USB. Look at how much trouble Meade has had over the years with USB
hubs on their mounts. The future is Ethernet, not USB.

Rolando


-----Original Message-----
From: gmillerok <grmok1@swbell.net>
To: ap-gto <ap-gto@yahoogroups.com>
Sent: Wed, Oct 17, 2012 5:35 pm
Subject: [ap-gto] Re: SERIAL PORTS (was: cannot connect gto CP3 to the SKy
6)


Apparently, there are quite a few other folks that don't have a problem
with
USB. All of my other devices such as main camera, guider, and focuser all
are
USB. The only device I have an issue is the one developed over 50 years
ago-the
serial port on the AP mount.

I understand the idea that "if it aint' broke, don't fix it." But again, I
had
to buy an expensive device to convert it to USB which AP recommends on
their
site to use that didn't work, and I would say that is a bigger problem
than any
issue in using USB-at least for me who is now $150 poorer and with a
device that
doesn't work.

Yes, I undertand the stability of RS-232. It should be, it was developed
over 50
years ago.

But when most computers and laptops sold today no longer even have serial
ports,
and you have to convert the serial to USB anyway, it seems like it may be
time
to catch up to the 21st century, even if it is a step backward. How about
this-put both a USB AND a RS232 port on the controller. Then you'd have
the
best(and worst) of both standards and could take your pick.

Gerald

--- In ap-gto@yahoogroups.com, "Steve Norvich" <snorvich@...> wrote:

This is an absolutely wonderful post. It reinforces my decision with
regard
to the Astro-Physics GTO1600. I was never comfortable with the
competition
s USB oriented solution.

snorvich@...
-------Original Message-------

From: Christopher Erickson
Date: 10/17/2012 3:19:59 PM
To: ap-gto@yahoogroups.com
Subject: RE: [ap-gto] Re: SERIAL PORTS (was: cannot connect gto CP3 to
the
SKy 6)


<SNIP>
"Roland, are your new mounts going to stick with the old serial port
standard? I hope not."
<SNIP>

Careful what you wish for...

Points to consider:

* For better or worse, RS-232 Serial has been the defacto-standard
universal
denominator for decades and will likely continue to be so for decades to
come. With hardly an exception, very microcontroller made in the world
today has an RS-232 serial port cast right in its silicon. Whether you
can
see them or not, RS-232 serial ports are EVERYWHERE. In fact all modern
"smart" refrigerators have hidden RS-232 serial ports that exist for the
service technicians armed with smart diagnostic tools. Even your car's
OBD-II or CANbus diagnostic interface has embedded RS-232-style serial
communications. Serial can be converted to just about anything (USB,
Ethernet, TCP/IP, Bluetooth, fiber-optic, Xbee wireless, etc.) USB can't
be
converted to anything without an intervening pair of computers and the
right
software on both ends, which usually doesn't exist. Not to mention the
expenses involved.

* RS-232 Serial can be run great distances (even thousands of kilometers)
using a great number of inexpensive media types and converters. USB can
barely make it across the average room without brain-splitting problems.

* Probably 90% of all problems with USB-Serial adapters are
driver-software
related. Just about everything coming out of China has Chinese-written
drivers and these have always been incomplete and highly-problematic. In
my
experience, the best and most trouble-free adapters use FTDI chips.
Prolific is a distant second place and everything else is almost complete
junk for any but the most basic of applications.

* For years, iOptron has offered GOTO mounts with USB interfaces instead
of
serial interfaces and the unending grief experienced by their users
related
to USB problems is infamous. In fact iOptron's most recent GOTO mounts
have
gone back to serial interfaces! Good news for people with iOptron mounts
with USB interfaces is that all iOptron did was incorporate a Chinese
USB-to-Serial chip into the mount and the iOptron microcontroller has a
serial interface on it! Cutting two traces and installing a connector has
allowed users to bypass iOptron's junky serial-to-USB adapter chip and
it's
horrible drivers.

* Having a serial interface on my mounts means I can easily control them
with a PC, wired/wireless smartphone or tablet computer. If it only had
USB, that usually eliminates the smartphone and tablet computer. SkyFi
has
a wireless USB adapter (expensive) coming out that may work with some
USB-only iOptron mounts but they are already warning people that it is a
"work in progress."

* USB 1 is obsolete. USB 2 is officially obsolete. USB 3 is current but
USB 4 is right around the corner. Most USB 3 ports these days don't
support
USB 1 peripherals. USB 4 ports are unlikely to support USB 1 or 2
peripherals. Why would I want to spend $10-20,000 for a premium mount
with
an interface that will be obsolete and unsupported in about five years?

Like I said, be careful what you wish for.

Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738
www.summitkinetics.com









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