On 2021-12-23, Tixy <[email protected]> wrote: > On Thu, 2021-12-23 at 14:20 +0000, Curt wrote: >> On 2021-12-23, Tixy <[email protected]> wrote: >> > >> > Still none the wiser of what hardware in the printer you would be >> > setting the baud rate of though, but as I'm ignorant of the insides of >> > 3D printers perhaps that's not a surprise. >> > >> >> You set the baud rate of the port is how I understand it. >> >> stty -F /dev/ACM0 115200 >> > > Yes, but that just sends an ioctl request to the Linux driver which > looking at the source code [1] translates it into sending control > message to the USB device of type USB_CDC_REQ_SET_LINE_CODING. > > So what does the 3D printer do when it receives this control packet? > What _hardware_ is it actually going to change the baud rate of? > I'm assuming here, as I said in my other reply [2], that the USB > interface is connected direct to the SoC running the printer, and not > to some USB serial adaptor which is then wired to the controlling CPU > hardware.
I'd think you'd change the baud rate of the port to some value copacetic to the printer via some negotiated agreement. I wouldn't be able to provide the technical, material details, I'm afraid. Of course, if you think this is all some sort of hooey, all I can say is there's oodles of hooey on the 3d printer technical forums, and I've fallen for it. :-) > [1] See acm_tty_set_termios() in drivers/usb/class/cdc-acm.c > [2] https://lists.debian.org/debian-user/2021/12/msg00818.html > --
