Hi Thomas,
I'm not sure I understood your question correctly, don't hesitate to
ask again in another way it's the case...
I used CBUS because I needed a simple switching system to control a 5v
USB powered power ramp (french link :
http://www.pearl.fr/cables/cables-electriques/multiprises/multiprise-usb-maitre-esclave_PE9938.html)
in order to power an external USB drive on or off at will.
The PC on wich it's connected it have it's USB plugs power always on
and so a bus powered USB drive would be always on. My external usb
drive had to be on only for backup duration and was not bus powered but
self powered. A nice geek problem :)
My father used this MM232R
module for another use, only to translate serial comm to usb as there
are fewer serial ports on PCs and he needed a product he created to
work without modifying all the existing hardware.
While discussing my problem with him, he show me the module and we
looked at the spec and noticed that there were 4 simple pins, easy to
use out of the box, that could deliver enough power to be used with a
transistor and output 5v and 75mA power to be used with my usb
controled power ramp. He gave me one of his modules.
The only thing I had to do was a small circuit plate with 6 components
and the module.
For my first try, I only connected one pin of the module, pin 12, wich
is PWREN# by default.So, even if I never succeded in creating my
program, the power would have been switched on USB sleep mode wich is
well triggered on my PC. That was the first thing I tried and it well
worked. When powering the PC on the led and so 5v were on and when
switching PC off everything became off too.
But I wanted to set my power ramp on or off at will. So I modified the
EEPROM of the FT232 chip on the module for the pin I used to be
controled on CBUS instead of automatic PWREN#. This needed me to use
FTDI EEPROM modification program MPROG that only runs under windows...
arg... Now that all works, I'll try to find another way to modify
EEPROM simply under linux.
So as I was now able to control the pin level using CBUS, I used
libftdi to make a small C program to switch my power ramp on or off.
The power ramp is off by default and when the pin 12 level is set to
low, it comes on. Magic of lasyness...
next step is to connect all the 4 pins to control 220v relays and so
switch on or off 4 power plugs :) And of course a nice box for all this
stuff that actualy fit into an ugly plastic and tape box...
So, it was on pupose and because of the out of the box CBUS fonctions.
But all is due to the fact that I had the module available.
Sorry for the long story, but you now have all details :)
Shears,
Nicolas.
Le 02.04.2009 20:51, Thomas Jarosch a écrit :
Do you use the CBUS mode on purpose or is it the only mode
that worked out of the box?
Cheers,
Thomas
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