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jbeale
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Joined: Tue Nov 22, 2011 11:51 pm
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Re: Multiple USB > Serial adaptors

Sun Jul 08, 2012 12:11 am

To answer my own question, I see that the Silicon Labs CP2102 device has an internal EEPROM which you can actually program yourself with your own serial number, and other info, using a utility from the silabs.com website.
http://www.silabs.com/products/interfac ... ridge.aspx

also, XRP (Hong Kong/Shenzen) is offering a USB-UART module with this chip for $7 shipped.
http://www.amazon.com/gp/product/B008BZ ... 00_s00_i00

the shipping is very slow, but next month I should know if this will work to give me unique serial numbers- seems like it should.

mpfisher
Posts: 5
Joined: Sat Mar 03, 2012 9:51 am

Re: Multiple USB > Serial adaptors

Fri Jul 13, 2012 11:06 am

FTDI chips can have EEPROMs programmed by manufacturers of these boards to have serial number disabled.
Try to connect them to your PC and check EEPROM configuration using FT_Prog utility from FTDI website.
Hope this help.

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scrishton
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Location: Settle, in the Yorkshire Dales
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Re: Multiple USB > Serial adaptors

Tue Jul 17, 2012 4:53 pm

After a busy few days I've made a bit more progress. I bought an FTDI USB to four port RS422 card from Farnell. The Pi immediately recognised all four ports without any problem, and my software appears to behave as I expect, though I only have access to a single VT machine to test it on at the moment. Following this success, I bought a second FTDI four port card, and the Pi again works as it should and will control all eight ports quite happily. If I add a Prolific adaptor, the error comes back.

Meanwhile, I borrowed another Raspberry Pi from a friend to see if it was just a hardware fault on my Pi. Strangely, this other Pi behaves quite differently, and slows right down when the Prolific adaptor is plugged in. Slows down to the point where it is almost single stepping my Python code. And it won't connect to my network. The borrowed one is from RS, whereas mine came from Element 14. Is there a difference? Are there settings stored on the Pi, not on the SD card?

Anyway, I think I can declare the original problem fixed if not actually solved, and I now have a working VT controller good enough to use in the real world. Does anyone else have any good Pi projects in television broadcasting?

Simon R.

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jbeale
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Re: Multiple USB > Serial adaptors

Tue Jul 17, 2012 7:57 pm

when you get a dramatic slowdown like that, one thing to check is if it's because thousands of error messages are being written into log files. Check /var/log/syslog for example.

luciusf
Posts: 1
Joined: Fri Dec 06, 2013 4:15 pm

Re: Multiple USB > Serial adaptors

Fri Dec 06, 2013 4:31 pm

Hi scrishton
Is your project still alive?
Where i work we have an old digibeta recorder, and I was able to control it to some degree with a crestron, which was also unused. Now I thought of trying the same with my raspberry pi as a fun project, and also to dive a little bit more into python.

Did you implemented the complete protocol?
I'm taking my firsts steps, and while I was able to play, stop and rewind, I have difficulties reading the timecode, because the values are encoded in hex, but seem to be the decimal value of the time.
0x15 -> 15sec (correct)
0x15 -> 21sec (wrong, but could be converted with python's int()
How did you overcome this problem?

best,
max


ps: i know it's not really the right thread, but i couldn't contact you directly, because my registration was too young

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scrishton
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Location: Settle, in the Yorkshire Dales
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Re: Multiple USB > Serial adaptors

Fri Dec 06, 2013 7:40 pm

Hi Max,

Yes, it's very much alive, and recording 'The Voice' at Media City this evening. It is currently written in Python, though I may re write it in C some time. If you search for Sony 9 pin protocol you can find most of the info you need online. Controlling a single machine is fairly straightforward, but the USB problems increase as you add more ports. I originally built it in a lego box with twelve channels, but it was a bit fragile and looked a little unprofessional so I eventually put it in a decent rack mount unit. I thought twelve channels would be plenty, but they quickly started wanting thirteen recorders so I added an extra board to give sixteen channels. 'The Voice' want seventeen of course.

I can email you a few bits of python code if it helps, but its far more fun to write your own.

Simon R.

WarHawk8080
Posts: 2
Joined: Sat Feb 17, 2018 8:10 pm

Re: Multiple USB > Serial adaptors

Sat Feb 17, 2018 8:13 pm

I was attempting to use the socat command to mirror the /dev/ttyUSB0 to another "virtual" device...but keep getting errors

socat /dev/ttyUSB0,raw,echo=0,crnl /dev/ttyUSB9,raw,echo=0,crnl

root@TronXYX1:/dev# socat /dev/ttyUSB0,raw,echo=0,crnl /dev/ttyUSB9,raw,echo=0,crnl
2018/02/17 14:12:28 socat[22826] E tcgetattr(6, 0xbeae4020): Inappropriate ioctl for device

Not sure if I need to create the device first...

Anyone wanna take a whack at it?

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