usb problems

[Gene Heskett]

On Sunday 12 October 2014 07:37:21 Gene Heskett did opine
And Gene did reply:
> On Sunday 12 October 2014 02:41:15 Nils Kassube did opine
> 
> And Gene did reply:
> > Gene Heskett wrote:
> > > I am in need of a tool that will effectively do a ping against a
> > > specified USB port, a port I know there is something on the other
> > > end of the cable and hub as I just had a printer do a test page
> > > over the same cabling. Basically I want to send a $55 down the
> > > cable once a second to a specified port, in thgius case
> > > /dev/ttyUSB1, for oscilloscope troubleshooting, at least as long
> > > as trouble doesn't shoot back... ;-)
> > 
> > If that /dev/ttyUSB1 device is a USB->serial converter, you could
> > treat it like any terminal device. Therefore, you can use stty to
> > disable the handshaking lines and set the desired speed (e.g. 100
> > Baud). Then echo the desired characters to the device:
> > 
> > stty -F /dev/ttyUSB1 clocal ospeed 100
> 
> stty -F /dev/ttyUSB1 clocal ospeed 115200
> stty -F /dev/ttyUSB1 clocal ispeed 115200
> while true;do echo -n "e" >/dev/ttyUSB1;sleep 1;done
> 
> > You can cancel the loop with CTRL-C.
> > 
> > 
> > Nils
> 
> This works, I can see the once a second red led flicker.  But when
> measured with the scope, the baud rate seems to be about 55800 (not
> 57600) unless that "e" is a 2 bits high, 2 bits low etc character.
> 
> Cheers, Gene Heskett

and after trying to use it at 115200, something is resetting it to 9600?

The .jar that makes a server out of this machine has a config, and that is 
all correct.  Showing:
Sending command: dw config set DeviceType serial	OK
Sending command: dw config set SerialDevice /dev/ttyUSB1	OK
Sending command: dw config set SerialRate 115200	OK
Sending command: dw config set SerialParity none	OK
Sending command: dw config set SerialStopbits 1	OK
Sending command: dw config set SerialDTR false	OK
Sending command: dw config set SerialRTS false	OK
Sending command: dw config set SerialFlowControl_RTSCTS_IN false	OK
Sending command: dw config set SerialFlowControl_RTSCTS_OUT false	OK
Sending command: dw config set [@name] CoCo 3 on /dev/ttyUSB1	OK
Sending command: dw config set [@desc] Autocreated 2014-10-12 07:30:40.164	
OK
Sending command: dw config set UseMIDI true	OK
Sending command: dw config set CurrentPrinter Text	OK
Sending command: dw config set Printer(1).OutputDir /CoCo/dwcache	OK

However, any attempt from the CoCo3 to do a directory listing is a read 
error because no data is coming back, the request for that data never 
arrived at this machines USB1 port.

I've taken the serial cable apart, its well soldered on both ends, and 
I've tried the 2nd of 2 identical converters, converters that worked just 
fine in April of this year.  Data is coming out of the CoCo3 with about a 
10 volt p-p swing centered on ground.  Humm, come to think about that, 
thats low, that circuit is running on the output of an old XT psu, and all 
voltages there are good, +-12 is at least +-11.5 volts.  I've blown 
another S.A.L.T chip would seem to be the correct diagnosis.

This is a jury rigged external power supply as the original was +-8 volts.  
The chip has been replaced once and I have one more spare.  Unfortunately, 
the data available on this chip is limited, and before I blow another, 
I'll order me up a set of 7808 and 7908's to make that +_12 look like what 
its used to.

Thanks Nils.

Cheers, Gene Heskett
-- 
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Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS