I'm responding as a user of CDC devices; I don't have specific explanations to your questions. However, I do use some CDC devices that enumerate as 'tty.usbmodem*' as if it's a standard legacy serial port (open, close, ioctl, struct termios, tcsetattr, cfset*speed, etc.). It works fine for me, but I know that the device I use deliberately ignores things like baud rate (since it's not a USB->Serial adapter, it's just enumerating as serial for convenience).
If I avoid running my custom code and just 'cat' the device, it also works for me. Depending on your device firmware and expected parameters (bits, parity, handshaking), you may be able to avoid the ioctl and attribute calls. I think it's really dependent on what the defaults are and what your device needs. lavrich On Nov 26, 2014, at 10:35 AM, Janice McLaughlin <[email protected]> wrote: > I have an application that will sometimes use a serial port with a kernel > driver if a user already has one installed for some other reason. I have a > user who has plugged in a usb serial cable that I *think* is from Freescale > Semiconductor. I don't have this cable myself, so have to get my customer to > run commands with it plugged in to figure it out. When plugged in, it gives a > USB Product ID of 0x0005, a Vendor ID of 0xffff, a Serial Number of 01234567 > and a Manufacturer: SERUSB. And it identifies as a USBSerial device. I don't > have the extended USB info for it. > > It's being claimed by the AppleUSBCDC driver and AppleUSBCDCACMControl and > AppleUSBCDCACMData. These drivers are not creating a usbserial device and > only creating a usbmodem device. I've looked through the open source drivers > and am learning about what the device must be advertising, but it already > does what it does and so I'd like to use it as is. > > So my question is, can I use /dev/tty.usbmodem* as a direct substitute for > /dev/tty.usbserial* ? At what point does the modem control logic "kick in"? > And so if I'm not using any of the BSD modem ioctl whatnot, will it stay out > of the way? > > Thanks, > Janice > > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Usb mailing list ([email protected]) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/usb/lavrich%40apple.com > > This email sent to [email protected]
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