On 2/8/24 04:00, Jan Stary wrote:
What HW do people use to read data from many serial ports simultaneously? My use case is reading the output of https://en.wikipedia.org/wiki/Electropalatography The device has eight serial port outputs; I need to read those at the computer side.Do I just stuff my box with 8 cereals, or is there something more elegant? Some multiplexing USB dongle? Jan
I have used a few modest-price USB to 8 port serial converters, they seem to "Just Work'. Here's one: uhub2 at uhub0 port 4 configuration 1 interface 0 "NEC product 0x0050" rev 2.00/1.00 addr 2 uftdi0 at uhub2 port 1 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 3 ucom0 at uftdi0 portno 1 uftdi1 at uhub2 port 2 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 4 ucom1 at uftdi1 portno 1 uftdi2 at uhub2 port 3 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 5 ucom2 at uftdi2 portno 1 uftdi3 at uhub2 port 4 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 6 ucom3 at uftdi3 portno 1 uftdi4 at uhub2 port 5 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 7 ucom4 at uftdi4 portno 1 uftdi5 at uhub2 port 6 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 8 ucom5 at uftdi5 portno 1 uhub3 at uhub2 port 7 configuration 1 interface 0 "NEC hub" rev 2.00/1.00 addr 9 uftdi6 at uhub3 port 1 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 10 ucom6 at uftdi6 portno 1 uftdi7 at uhub3 port 2 configuration 1 interface 0 "FTDI FT232R USB UART" rev 2.00/6.00 addr 11 ucom7 at uftdi7 portno 1 And here's another one: uhub3 at uhub0 port 4 configuration 1 interface 0 "NEC hub" rev 2.00/1.00 addr 2 umcs0 at uhub3 port 1 configuration 1 interface 0 "MosChip MCS7840 Serial" rev 2.00/0.01 addr 3 ucom0 at umcs0 portno 0: usb0.4.00001.0 ucom1 at umcs0 portno 1: usb0.4.00001.0 ucom2 at umcs0 portno 2: usb0.4.00001.0 ucom3 at umcs0 portno 3: usb0.4.00001.0 umcs1 at uhub3 port 2 configuration 1 interface 0 "MosChip MCS7840 Serial" rev 2.00/0.01 addr 4 ucom4 at umcs1 portno 0: usb0.4.00002.0 ucom5 at umcs1 portno 1: usb0.4.00002.0 ucom6 at umcs1 portno 2: usb0.4.00002.0 ucom7 at umcs1 portno 3: usb0.4.00002.0 I'm not going to provide names or product numbers, because I've been using both for well over six or seven years now, so anything you buy new will almost certainly be "different". Both were under $150US at the time. Selection was based on "If this doesn't work, am I going to cry about the wasted money?" process. Both worked. You may get better results with a bigger price tag, you may not. One is basically just a snoot-load of individual FTDI USB to Serial chips behind a couple USB hubs. The other is a couple four port USB to serial chips, also behind a USB hub. OpenBSD handles both just fine. I've had occasional issues where the things "break" (can't establish communications with the serial ports) and to get serial ports running again requires a physical unplug/plug-in or an OS reboot. So far, a reboot has always fixed it for me. So it shouldn't be on a machine that requires a maintenance window for reboot, but rather a more-or-less application dedicated system. Dunno if all devices do this, but I've seen some people complain about this on other OSs, too -- I kinda have the impression the FTDI chips were designed to be plugged in and unplugged a lot, not left attached and operating for months at a time, but ... no idea if there is anything to that other than my speculation (I don't use the MosChip box as much as the FTDI, so I really can't say if it has the same problem. And thinking about it, I don't recall having to reboot the system the FTDI device is attached to in a while due to port lockup, so maybe it's fixed in the OS, maybe it has become so automatic to me, I just do it and don't log it in my brain). Nick.
