Go to advanced search

by scrishton
Mon Feb 25, 2013 11:19 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: RS422 Port
Replies: 9
Views: 14723

Re: RS422 Port

You can use a USB to RS422 adaptor. There are two common chipsets, the Prolific PL2303 and the FTDI. Early FTDI adapters can have driver problems, but the later ones work very well. I had problems trying to use multiple PL2303 adapters, but that was a while ago and the USB system is getting much bet...
by scrishton
Tue Feb 12, 2013 10:23 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Old Meets New
Replies: 59
Views: 9040

Re: Old Meets New

As you weren't the original purchaser of your MK14, you had a narrow escape. Three times (MK14, ZX81, Spectrum) I had to endure that nonsense from Sinclair, advertising and taking payment for goods half a year before they actually arrived. It's amazing that I was so loyal for so long. But by the ti...
by scrishton
Tue Feb 12, 2013 7:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Old Meets New
Replies: 59
Views: 9040

Re: Old Meets New

It's a 6502 in the UK101. I probably have one somewhere in the loft. I suspect the machine has more wrong with it than lack of CPU, but one day when I have spare time again I'll sort it out. Forth on the Jupiter Ace was a truly elegant language. In my mis-spent youth I spent some time disassembling ...
by scrishton
Tue Feb 12, 2013 6:42 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Old Meets New
Replies: 59
Views: 9040

Re: Old Meets New

You could 3d print one of these though...
Image
Digi Comp 1, made around late sixties and sold as a plastic kit. Three bit mechanical computer, programmed by adding short plastic straws on the front and back pegs.
by scrishton
Tue Feb 12, 2013 2:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Old Meets New
Replies: 59
Views: 9040

Re: Old Meets New

I was given a Mk14 back in the early eighties in payment for repairing a UK101. The Mk14 was also faulty - the crystal wasn't rattling. But as you pointed out, Sir Clive had used the very common - and cheap - colour subcarrier crystal and I had one of those on my shelf, even the right vintage. It's ...
by scrishton
Mon Jan 28, 2013 1:21 pm
Forum: Troubleshooting
Topic: powered USB hub is powering my Pi?
Replies: 11
Views: 2399

Re: powered USB hub is powering my Pi?

What are your USB problems? There is a long thread at http://www.raspberrypi.org/phpBB3/viewt ... 28&t=12097 with a lot of information about USB troubles if you have a few hours to spare, and a lot has changed since that thread was closed.

Simon R.
by scrishton
Mon Jan 28, 2013 1:12 pm
Forum: Troubleshooting
Topic: powered USB hub is powering my Pi?
Replies: 11
Views: 2399

Re: powered USB hub is powering my Pi?

This is not unusual. The USB standard says that hubs should not provide power to the 'upstream' connector, but many do anyway. The early version of the Raspberry Pi had a bit of a problem with this as the polyfuses which are supposed to protect the USB ports would trip from the current drawn by powe...
by scrishton
Sun Jan 13, 2013 1:29 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

OK, I'll try to put the LSUSB results up. The devices use the FTDI FT4232H chip. I have just tried changing the cards to work in D2XX Direct mode instead of Virtual Com Port mode, but can see no difference in behaviour. I'm wondering if it's worth trying to change the port latency with FT_SetLatency...
by scrishton
Sat Jan 12, 2013 11:35 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

Still trying to get more than one FTDI serial port open whilst still being able to use the keyboard. I tried two different USB keyboards. One just stops responding with no errors reported in dmesg once more than one port is opened. The other one, an A4TECH KL-5, repeatedly disconnects and reconnects...
by scrishton
Thu Jan 10, 2013 7:55 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

Thanks very much for your help M33P. Is it possible to set the USB serial device to work without interrupts? My remote devices never send data spontaneously, only in response to commands or requests from the host. And the number of bytes in the response packet are shown in the header, so the host al...
by scrishton
Thu Jan 10, 2013 11:02 am
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

M33P, with your bug fix from yesterday my controller was able to run all night without the usual crash I get from 3.6.11. Still unable to read keyboard with more than one FTDI card. I just tried a different USB keyboard - this still fails in the same way, but interesting to note that the numlock lig...
by scrishton
Thu Jan 10, 2013 12:26 am
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

Hi M33P. I have run rpi-update, rebooted, and tried my 12 channel RS422 system again. It still fails to read the keyboard if more than one FTDI card is opened. The only way to get back is to unplug the USB hub to crash out of the program. I have just tonight made some changes to my program so that i...
by scrishton
Wed Jan 09, 2013 11:49 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

I am currently getting rid of my LEGO and building the whole system into a compact 1U 19" rack mount box complete with internal power supply, front panel with 16 Cat5 connections, rear panel with HDMI, PAL video and four USB connections. And I have used it as a VT controller to record several progr...
by scrishton
Mon Jan 07, 2013 12:30 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

However, with updated versions of Raspbian I can only use one 4-port card at a time. Tried kernel 3.6.y yet via https://github.com/Hexxeh/rpi-update ? Yes, I have tried '3.6.11+ #348 PREEMPT Tue Jan 1 16:33:22 GMT 2013 armv61' and it stops the keyboard working if more than one FTDI card is opened. ...
by scrishton
Fri Jan 04, 2013 7:16 pm
Forum: Troubleshooting
Topic: USB redux
Replies: 514
Views: 230122

Re: USB redux

I have been working on a USB to serial project on the RasPi for some months now, with quite a lot of success. However, later versions of the operating system seem to give more problems. With an early version of Raspbian, 3.1.9 #168 from 14th July, I can reliably open and read/write twelve RS422 seri...
by scrishton
Tue Jul 17, 2012 4:53 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

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 momen...
by scrishton
Mon Jun 18, 2012 10:44 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

Yes, Sony still use RS422. And despite everyone believing that VHS wiped out Beta, Beta is still alive and kicking, albeit Betacam SR, Digibeta, and HDCam. And meanwhile, at the shiny new studio complex at MediaCity in Salford, where everything is designed to be tapeless, recorded straight onto serv...
by scrishton
Mon Jun 18, 2012 7:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

I tried running karl101's code today, and it came up with an 'already open' error, which suggests that it uses a different version of pyserial. So I've made up an SD card with Raspbian, fully updated, with pyserial2.5 rather than the 2.6 I used earlier. The program only found one ttyUSB port. What R...
by scrishton
Sun Jun 17, 2012 1:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

Thanks Karl and rgh. That sounds promising. Unfortunately I'm at work today, and though I have my Pi with me, lots of DVI monitors in front of me, and the Pi seems happy to take power from the waveform monitor on my desk, the only spare keyboard I can find has a broken USB cable and won't play. So I...
by scrishton
Tue Jun 12, 2012 7:38 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: /dev/ttyUSB0 as a serial link
Replies: 11
Views: 7573

Re: /dev/ttyUSB0 as a serial link

therealeasterbunny, my cheapo PL2303 USB to RS422 adaptors seem to have a totally non standard pinout on their 9-pin connectors. Took me a while to sort out how they should be wired, then found that Mr Sony had also come up with his own 9-pin pinout on the back of the video tape machines I'm trying ...
by scrishton
Tue Jun 12, 2012 4:00 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

I have now tried the program on Debian Wheezy and Arch Linux, and the same thing happens. Also with a different power supply, different hub and different pl2303 USB adaptors. So the only common link seems to be the Raspberry Pi. And the Lego, but that's probably a red herring.
by scrishton
Sun Jun 10, 2012 9:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

Good thought, patrikg, but that doesn't seem to make any difference. But when I tried it on the netbook I was running through sudo to get permission for the serial ports, so there may be something in it. I have tried running the open command in a try except loop to see if it would work if I kept ret...
by scrishton
Sun Jun 10, 2012 8:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Re: Multiple USB > Serial adaptors

Thanks for the replies. rew, changing ttyUSB numbers makes no difference, it always fails when I try to open a second port. Even with a long (six second) sleep between ports it still fails. Running strace the failure looks like... open("/dev/ttyUSB1", O_RDRWIO_NOCTTYIO_NONBLOCKIO_LARGEFILE) = -1 EPR...
by scrishton
Fri Jun 08, 2012 11:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple USB > Serial adaptors
Replies: 31
Views: 23194

Multiple USB > Serial adaptors

I'm working on a little project to control video recorders from a Raspberry Pi using 'Sony 9-pin protocol' which is RS422. The hardware is a Lego clad Pi powered by an iPhone charger with a Logitech K260 wireless keyboard and mouse, USB hub and various USB to RS422 or RS232 and converter combination...

Go to advanced search