On Mon, Jul 21, 2014 at 06:55:43PM +0000, Amadeus W.M. wrote: > On Mon, 21 Jul 2014 11:18:28 -0700, Greg KH wrote: > > > On Mon, Jul 21, 2014 at 03:19:00AM +0000, Amadeus W.M. wrote: > >> Not sure if this is the right venue for this question, please direct me to > >> the right place if it's not. > >> > >> I have a C program that opens the serial port /dev/ttyS0 and sends commands > >> (as strings) back and forth to a pan-tilt-zoom camera. That works very well, > >> but I want to use the camera with a Raspberry Pi, which of course does not > >> have a serial port (RS232). One option is to use a RS232 to usb adapter and > >> rewrite the C code for the usb port. So how do I go about that? Is > >> usb serial port programming possible and documented anywhere? > > > > Nothing to "rewrite", just point your code at /dev/ttyUSB0 instead, and > > away you go... > > Thanks for the prompt answer! > > That's what I was hoping for, and I would have tried that, but I don't > have any /dev/ttyUSBX. I am connecting the camera to a usb to RS232 > cable: > > http://www.amazon.com/gp/product/B000BI95W0/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 > > Does this mean my adapter is not supported by linux? Also, nothing > happens in /var/log/messages when I plug the cable into the usb port. > This is my lsusb: > > 1) root:~> lsusb > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 005 Device 003: ID 0c45:1050 Microdia CF Card Reader > Bus 005 Device 002: ID 046d:c016 Logitech, Inc. Optical Wheel Mouse > Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub > Bus 004 Device 008: ID 0764:0501 Cyber Power System, Inc. CP1500 AVR UPS > Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub > Bus 003 Device 005: ID 04fc:0561 Sunplus Technology Co., Ltd Flexcam 100 > Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub > Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub > > No trace of the adapter. What is the: Bus 004 Device 008: ID 0764:0501 Cyber Power System, Inc. CP1500 AVR UPS device? > Should /dev/ttyUSB0 pop up when I plug the adapter into the usb port, > even before I connect anything to the serial port of the cable? Yes. What happens in the kernel log when you plug the device into the system? Try doing: dmesg -c # plug in the adapter now dmesg to just see the log messages for that, and not the whole kernel boot log. > If the adapter is not supported, can I write a driver for it? I'll be happy to, > with a little guidance to get me started. Any pointers? Odds are the device id just needs to be added to an existing driver as I do not know of any "new" usb-serial converter chips that Linux does not already support. thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
